Ink jet recording ink, ink jet recording ink set, recording method, recorded matter and ink jet recording apparatus

ABSTRACT

An ink jet recording ink has excellent dispersion stability and ejection stability and is capable of providing images free from bleeding. Such an ink exhibits excellent color development and rubbing resistance. The ink jet recording ink comprises a pigment dispersed by a polymer; water; at least one compound selected from the group consisting of an acetylene glycol surfactant and an acetylene alcohol surfactant; and 1,2-hexanediol. The pigment dispersed by the polymer is produced by a phase conversion emulsification, an emulsion polymerization, an acid deposition or a forced emulsification. The ink has a surface tension between 25 mN/m and 45 mN/m.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority under 35U.S.C. §120 on, application Ser. No. 11/981,349, filed Oct. 31, 2007,which is a continuation of application Ser. No. 10/048,909, filed Jun.18, 2002, now U.S. Pat. No. 7,307,109, which is a U.S. national phaseapplication of PCT/JP01/04787, filed Jun. 6, 2001. The content of eachof these related applications is incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to an ink jet recording ink, an ink jetrecording ink set, a recording method, recorded matter, and an ink jetrecording apparatus.

BACKGROUND ART

Ink jet recording is a method of recording letters and figures on thesurface of a recording object by ejecting ink droplets onto the objectthrough fine nozzles. For such an ink jet recording system, for example,practically employed are a method of recording letters and symbols onthe surface of a recording object by converting electronic signals intomechanical ones by the use of an electrostrictive device, followed byintermittently ejecting the ink stored in a nozzle head onto the objectaccording to the thus-converted mechanical signals; and a method ofrecording letters and symbols on the surface of a recording object byrapidly heating a part of the ink stored in a nozzle head and nearest tothe ejecting orifices of the nozzle to cause bubbling, andintermittently ejecting the ink onto the object by the volume expansionof the ink bubbles.

Ink for such ink jet recording is required to have various specificcharacteristics. For example, for printing on paper which is anrecording object, the requirements of the ink to be used are that itdoes not cause bleeding, it quickly dries thereon, it enables uniformrecording on various kinds of recording objects, and it does not mixwith the neighboring ink in multi-color printing to form color prints.

For ink jet recording ink, generally used are those prepared bydissolving various kinds of water-soluble dyes in aqueous media.Recently, those prepared by dispersing pigments in aqueous media havebeen provided, and this is characterized in that the pigment-containinginks are superior to the water-soluble dye-containing ones inwater-resistance and light-resistance.

Many conventional pigment-containing inks are to ensure the quality ofprinted matter by mainly suppressing their penetration into printingpaper to thereby prevent the paper surface from being too much wettedwith the inks and make the ink droplets stay near the paper surface.However, the inks of this type are problematic in that theirapplicability to all kinds of paper is low. Specifically, one problem isthat the difference in the degree of bleeding depending on the kind ofpaper is large. In particular, for regenerated paper that comprises manyunspecific paper materials, the difference in the wettability of inkswith such different paper materials constituting it has an influence onthe degree of ink bleeding thereon, and, as a result, the print qualityis unstable. Another problem is that the inks of the type mentionedabove take a long time until the printed area is dried. In particular,in multi-color printing for color prints, the neighboring inks aremixed. Still another problem is that some pigment remains on the printedpaper, and therefore the printed paper is deteriorated in abrasionresistance.

To solve the problems, adding a penetrant to ink is tried for improvingink penetration into paper. For example, some examples of using glycolethers are disclosed as follows. An example of using triethylene glycolmonomethyl ether is disclosed in Japanese Patent Laid-Open No.147861/1981; and an example of using ethylene glycol, diethylene glycolor triethylene glycol ethers is in Japanese Patent Laid-Open No.111165/1997. Addition of diethylene glycol monobutyl ether is proposedin U.S. Pat. No. 5,156,675; addition of an acetylene glycol surfactant,Surfynol 465 (by Nisshin Chemical) is in U.S. Pat. No. 5,183,502; and acombined use of diethylene glycol monobutyl ether and Surfynol 465 is inU.S. Pat. No. 5,196,056. In U.S. Pat. No. 2,083,372, proposed is usingdiethylene glycol ethers in ink.

For preparing conventional pigment-containing inks, in general, pigmentis dispersed in an aqueous medium by a dispersant such as surfactant orpolymer dispersant. However, this is problematic in that it is not easyto improve the ink penetration while ensuring the pigment dispersionstability in ink.

In the inks of pigment dispersion prepared by dispersing pigment by adispersant such as surfactant or polymer dispersant so as to improve theink penetration, the pigment merely adsorbs the dispersant on itssurface. Therefore, when the ink of the type is ejected through finenozzles, the adsorbed dispersant drops off in case where it receivesstrong shear force, and the pigment dispersibility in the ink islowered, thereby the ejection may tend to become unstable. In addition,when the ink is stored for a long time, the dispersibility may tend tobecome unstable. To solve the problems, an increase of the additionamount of the dispersant can be considered. In such a case, however, theamount of the dispersant not adsorbed by the pigment but stilldissolving in the ink increases, and therefore the ink often involvesthe phenomena that when used in printing plain paper or regeneratedpaper, it readily cause bleeding and it wets the periphery of thenozzles to readily make the ejection unstable. In addition, in casewhere ink of a pigment dispersion prepared by dispersing a pigment by adispersant such as surfactant or polymer dispersant to ensure improvedpenetration is used in printing on plain paper or regenerated paper, thepigment which is the colorant component therein tends to hardly remainon the surface of the fibers constituting the surface of the recordingmedium and, as a result, there is a tendency that the printed density isinsufficient and the color development is not good. Moreover, ingeneral, the dispersant not originally adsorbed by the pigment butdissolving in ink, or the dispersant having dropped off from the pigmenttend to increase the viscosity of the ink, and therefore the pigmentcontent of the ink is limited in many cases. Therefore, the ink of thistype could not ensure sufficient printed density especially on plainpaper or regenerated paper, and hence good color development cannot beattained and high-quality images are hardly obtained. In addition, whenink is left in heads for a long time, its dispersion stability isdeteriorated and there have been cases where the ejection of the inkfrom the nozzles of a printer becomes difficult.

With respect to these problems, inks using pigments having subjected tosome surface treatment to their surfaces have been proposed forimproving ejection stability, dispersion stability, printed density andcolor development property. Examples of the inks using treated pigmentsare as follows. For example, inks using pigment particles oxidized ontheir surfaces are proposed in Japanese Patent Laid-Open No.319444/1996; inks using encapsulated fine pigment particles are proposedin Japanese Patent Publication No. 94634/1995 and Japanese PatentLaid-Open No. 59715/1996; and inks using pigment particles having graftpolymerized a polymer on their surfaces are proposed in Japanese PatentLaid-Open Nos. 339516/1993, 302227/1996, 302228/1996 and 81647/1996.

In addition to the above proposals, further proposed are inks using apigment coated with a resin having film-forming property through phaseconversion emulsification at room temperature, as disclosed in JapanesePatent Laid-Open Nos. 218015/1996, 295837/1996, 3376/1997, 183920/1996,46075/1998, 292143/1998, 80633/1999, 349870/1999 and 7961/2000; and inksusing a pigment coated with an anionic group-containing organic polymercompound through acid deposition, as disclosed in Japanese PatentLaid-Open Nos. 31360/1997, 217019/1997, 316353/1997, 104834/1997,151342/1997, 140065/1998, 152424/1999, 166145/1999, 166145/1999,199783/1999 and 209672/1999. However, inks using the colorant preparedthrough phase conversion emulsification or acid deposition incombination with a surfactant, as a penetrant, such as glycol ethers oracetylene glycol surfactants are still unsatisfactory especially inpoint of the image quality on plain paper or regenerated paper.Specifically, the resin not absorbed by the pigment exists in the inkwith being dissolved therein; and the resin adsorbed by the pigmentdrops off to increase the amount of the resin dissolving in the ink. Forthese reasons, when the ink is used in printing on plain paper orregenerated paper, the pigment which is the colorant component hardlyremain on the surface of paper-forming fibers on the recording mediumsurface. Therefore, it is difficult to obtain a sufficient printeddensity and the color development is not good. In addition, bleedingreadily occurs. Furthermore, it tends to cause a phenomenon that the inkwets the periphery of the nozzles to readily make the ejection unstable.

The present invention is to solve at least some of the problemsdescribed above. Accordingly, an object thereof is to provide an ink jetrecording ink having excellent dispersion stability and ejectionstability and being capable of providing a high-quality image free frombleeding and that has high printed density and excellent colordevelopment property even on plain paper and regenerated paper.

Another object of the invention is to provide an ink jet recording inkcapable of attaining satisfactory rubbing resistance not only on plainpaper and regenerated paper but also on other recording media such ascoated paper, etc.

A still other object of the invention is to provide an ink jet recordingink that has excellent long-term storage stability.

DISCLOSURE OF THE INVENTION

The present inventors invented an ink that has excellent propertiessuitable for ink jet recording ink. Specifically, it was found that theink has good dispersion stability and ejection stability, and enablesstable printing operation with no trouble of nozzle clogging for a longtime, and further found that, when used in printing on recording mediasuch as plain paper, regenerated paper and coated paper, it can form animage having a good drying property, being free from bleeding, havinghigh printed density and excellent color development property andrubbing resistance. Embodiments of the invention are set forth below.

An ink jet recording ink comprising a pigment dispersed by a polymer;water; at least one compound selected from the group consisting of anacetylene glycol surfactant and an acetylene alcohol surfactant; and1,2-hexanediol. The pigment dispersed by the polymer is produced by aphase conversion emulsification, an emulsion polymerization, an aciddeposition or a forced emulsification. The ink has a surface tensionbetween 25 mN/m and 45 mN/m.

The ink jet recording ink may further comprise glycol ether. The glycolether may be di(tri)ethylene glycol monobutyl ether, (di)propyleneglycol monobutyl ether, or both.

The ink jet recording ink may further comprise at least one compoundselected from the group consisting of polyalcohols and compounds of thefollowing formula (1):R-EOn-POm-M  (1)where

R represents a C₄₋₁₂ alkanol, cycloalkanol, phenol and/or naphtholgroup, which is linear and/or another isomer;

EO represents an ethyleneoxy group;

PO represents a propyleneoxy group;

n and m each indicate the mean value of the repetitive units in thewhole system;

the indication of EO and PO merely represent the presence thereof in themolecule, not limiting their order;

M represents a hydrogen atom, a sulfonate group, a phosphate groupand/or a borate group, and the counter ion of the sulfonate group, thephosphate group and/or the borate group is a hydrogen atom, an alkalimetal, an inorganic base and/or an organic amine.

In the ink jet recording ink, the polymer content may be 10% by weightor higher based on the whole amount of the pigment.

The polymer itself may comprise, as a main component, at least onemember selected from the group consisting of vinyl polymers, polyesters,polyamides, polyimides, silicon-containing polymers andsulfur-containing polymers. The polymer may have a crosslinkedstructure.

Other characteristics and properties of the polymer may include one ormore of the following. The polymer may have a solubility parameter offrom 11 to 14 cal/cm³, where the difference between the solubilityparameter of a liquid component in the ink and that of the polymer is1.0 cal/cm³ or greater. The polymer may have an acid value of from 20 to200 KOH mg/g. The polymer may have a glass transition temperature of nothigher than 25° C. The polymer may have a film-forming temperature ofnot higher than 25° C.

In the ink jet recording ink, the pigment dispersed by the polymer mayfurther contain a hardly water-soluble substance. The hardlywater-soluble substance may have a solubility in water of 10% by weightor lower.

The ink jet recording ink may have a surface tension of at most 37 mN/m.

In the ink jet recording ink, the pigment may be an inorganic pigmentselected from the group consisting of copper oxides, iron oxides,titanium oxides, and carbon blacks, or an organic pigment selected fromthe group consisting of azo pigments, phthalocyanine pigments, perylenepigments, perinone pigments, anthraquinone pigments, quinacridonepigments, dioxane pigments, thioindigo pigments, isoindolinone pigments,quinofuranone pigments, nitro pigments, nitroso pigments, and anilineblack.

In the ink jet recording ink, the content of 1,2-hexanediol in the inkmay be from 0.5% by weight to 10% by weight.

In the ink jet recording ink, an addition amount of 1,2-alkylene glycolin the ink may be less than 10 times an addition amount of the acetyleneglycol surfactant and/or the acetylene alcohol surfactant.

In the event a polymerizable surfactant is employed, it may be acompound having the following formula (1):

wherein R represents a hydrogen atom, or a hydrocarbon group having from1 to 12 carbon atoms; n indicates a number falling between 2 and 20; Mrepresents an alkali metal, an ammonium salt, or an alkanolamine.

Alternatively, any polymerizable surfactant may be a compound of thefollowing formula (II):

wherein R′ represents a hydrogen atom or a hydrocarbon group having from1 to 12 carbon atoms; n indicates a number falling between 2 and 20; Mrepresents an alkali metal, an ammonium salt, or an alkanolamine.

BEST MODES OF CARRYING OUT THE INVENTION

The ink jet recording ink of the invention (hereinafter sometimesreferred to simply as “ink”) has a feature that it contains: a colorantof a pigment and/or dye enveloped in a polymer; and water, and containsat least one compound selected from the group consisting of acetyleneglycol surfactants, acetylene alcohol surfactants, glycol ethers, and1,2-alkylene glycols.

Preferably, the ink jet recording ink is so designed that the content ofthe at least one compound therein, which is selected from the groupconsisting of acetylene glycol surfactants, acetylene alcoholsurfactants, glycol ethers and 1,2-alkylene glycols, falls between 0.5%by weight and 30% by weight. If the content is smaller than 0.5% byweight, the effect of improving penetration readily becomes insufficientand the print quality is hardly improved. On the other hand, if thecontent is larger than 30% by weight, the ink viscosity increases tomake the handling thereof difficult, and a further larger amountaddition thereof tends to not show an effect of further improving theprint quality. More preferably, the content falls between 1% by weightand 15% by weight.

Particularly preferably, the ink of the invention contains: a colorantof a pigment and/or dye enveloped in a polymer; and water, and contains:at least one compound selected from the group consisting of acetyleneglycol surfactants and acetylene alcohol surfactants; and at least onecompound selected from the group consisting of glycol ethers and1,2-alkylene glycols.

Also preferably, the ink jet recording ink contains at most 5% by weightof at least one compound selected from the group consisting of acetyleneglycol surfactants and acetylene alcohol surfactants. If the content ofthe compound is larger than 5% by weight, its effect to improve theprint quality has peaked and the ink viscosity increases to make thehandling thereof difficult. In addition, the ink readily adheres to thetip of a head and the printed image tends to be disordered. Morepreferably, the content of the compound falls between 0.1% by weight and2% by weight.

One preferred embodiment of the ink jet recording ink contains at most5% by weight of at least one compound selected from the group consistingof acetylene glycol surfactants and acetylene alcohol surfactants, andcontains at least 1% by weight of at least one compound selected fromglycol ethers and 1,2-alkylene glycols.

The acetylene glycol surfactants and acetylene alcohol surfactants areeffective to improve ink penetration even though their amount in ink issmall. For this reason, therefore, when the content of the at least onecompound selected from the group consisting of acetylene glycolsurfactants and acetylene alcohol surfactants in ink is at most 0.5% byweight, it is desirable that the content of the at least one compoundselected from the group consisting of glycol ethers and 1,2-alkyleneglycols in the ink is at least 1% by weight for ensuring improved printquality.

In case where the ink jet recording ink contains at least 0.5% by weightof the at least one compound selected from the group consisting ofacetylene glycol surfactants and acetylene alcohol surfactants, it isdesirable that the ratio by weight of the compound to the 1,2-alkyleneglycol in the ink is controlled to fall between 1:0 and 1:10 from theviewpoint of print quality. If the addition amount of the 1,2-alkyleneglycol in the ink is over 10 times the acetylene glycol surfactantand/or the acetylene alcohol surfactant, not only the effect ofimproving the print quality tends to have peaked, but also an adverseeffect of increasing the ink viscosity tends to occur.

From the viewpoint of the print quality improvement, suitable examplesof the at least one compound selected from the group consisting ofacetylene glycol surfactants and acetylene alcohol surfactants includeat least one compound selected from the group consisting of2,4-dimethyl-5-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol,3,6-dimethyl-4-octyne-3,6-diol, and adducts of those2,4-dimethyl-5-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol and3,6-dimethyl-4-octyne-3,6-diol each with at most 30, on average number,of ethyleneoxy groups and/or propyleneoxy groups added thereto.

Of the adducts of 2,4-dimethyl-5-hexyn-3-ol,2,4,7,9-tetramethyl-5-decyne-4,7-diol and 3,6-dimethyl-4-octyne-3,6-dioleach with ethyleneoxy groups and/or propyleneoxy groups added thereto,those in which the average number of the ethyleneoxy groups and/orpropyleneoxy groups added thereto is larger than 30 tend to cause heavybubbling of the ink to deteriorate the print quality improving effect.Therefore, the number of the groups in the adducts is preferably at most30.

In case where the ink contains an acetylene alcohol surfactant, adissolution promoter may be added thereto. Preferred examples of thedissolution promoter include 1,3-dimethyl-2-imidazolidinone,2-pyrrolidone, and N-methyl-2-pyrrolidone.

The glycol ethers for use herein include diethylene glycol mono(C₁₋₈alkyl)ethers, triethylene glycol mono(C₁₋₈ alkyl)ethers, propyleneglycol mono(C₁₋₆ alkyl)ethers, and dipropylene glycol mono(C₁₋₆alkyl)ethers. These compounds may be used singly or as a mixture of twoor more thereof.

Specific examples thereof include ethylene glycol monomethyl ether,ethylene glycol monoethyl ether, ethylene glycol mono-iso-propyl ether,ethylene glycol monobutyl ether, ethylene glycol mono-t-butyl ether,ethylene glycol monomethyl ether acetate, diethylene glycol monomethylether (DEGmME), diethylene glycol monoethyl ether (DEGmEE), diethyleneglycol monopropyl ether (DEGmPE), diethylene glycol mono-iso-propylether, diethylene glycol monobutyl ether (DEGmBE), diethylene glycolmono-t-butyl ether, diethylene glycol monopentyl ether (DEGmPeE),diethylene glycol monohexyl ether (DEGmHE), diethylene glycol monoheptylether (DEGmHpE), diethylene glycol monooctyl ether (DEGmOE), triethyleneglycol monomethyl ether (TEGmME), triethylene glycol monoethyl ether(TEGmEE), triethylene glycol monopropyl ether (TEGmPE), triethyleneglycol monobutyl ether (TEGmBE), triethylene glycol monopentyl ether(TEGmPeE), triethylene glycol monohexyl ether (TEGmHE), triethyleneglycol monoheptyl ether (TEGmHpE), triethylene glycol monooctyl ether(TEGmOE), propylene glycol monomethyl ether (PGmME), propylene glycolmonoethyl ether (PGmEE), propylene glycol monopropyl ether (PGmPE),propylene glycol mono-iso-propyl ether, propylene glycol monobutyl ether(PGmBE), propylene glycol mono-t-butyl ether, propylene glycolmonopentyl ether (PGmPeE), propylene glycol monohexyl ether (PGmHE),dipropylene glycol monomethyl ether (DPGmME), dipropylene glycolmonoethyl ether (DPGmEE), dipropylene glycol monopropyl ether (DPGmPE),dipropylene glycol mono-iso-propyl ether, dipropylene glycol monobutylether (DPGmBE), dipropylene glycol monopentyl ether (DPGmPeE), anddipropylene glycol monohexyl ether (DPGmHE). Since a larger alkyl grouphas higher hydrophobicity, the alkyl group therein is preferably methyl,ethyl, propyl or butyl, for ensuring good print quality on plain paper.

Particularly preferably, the glycol ether is di(tri)ethylene glycolmonobutyl ether and/or (di)propylene glycol monobutyl ether.

The (di)propylene glycol monobutyl ether is meant to indicate propyleneglycol monobutyl ether (PGmBE) (solubility parameter δ=8.9) and/ordipropylene glycol monobutyl ether (DPGmBE) (δ=8.2). The di(tri)ethyleneglycol monobutyl ether is meant to indicate diethylene glycol monobutylether (DEGmBE) (δ=8.96) and/or triethylene glycol monobutyl ether(TEGmBE) (δ=8.86).

The (di)propylene glycol monobutyl ether content in the ink ispreferably at most 10% by weight for imparting satisfactory inkpenetration suitable for ink jet recording ink. If it is larger than 10%by weight, not only the effect of improving the print quality tends tohave peaked, but also an adverse effect of increasing the ink viscositytends to occur. In addition, since the solubility in water of the(di)propylene glycol monobutyl ether is not so high, the additionthereof in an amount larger than 10% by weight in the ink tends tonecessitate a dissolution promoter. More preferably, the (di)propyleneglycol monobutyl ether content of the ink falls between 0.5% by weightand 5% by weight.

In case where the ink jet recording ink contains at least 0.5% by weightof the at least one compound selected from the group consisting ofacetylene glycol surfactants and acetylene alcohol surfactants, it isdesirable that the ratio by weight of the compound to the (di)propyleneglycol monobutyl ether in the ink is controlled to fall between 1:0 and1:10 for ensuring good print quality. If the amount of the (di)propyleneglycol monobutyl ether in the ink is over 10 times the acetylene glycolsurfactant and/or the acetylene alcohol surfactant, the effect ofimproving the print quality tends to have peaked, and a further largeramount addition thereof gives merely a small effect, rather readilycauses an adverse effect of increasing the viscosity.

The di(tri)ethylene glycol monobutyl ether content in the ink ispreferably at most 20% by weight for imparting satisfactory inkpenetration suitable for ink jet recording ink. If it is larger than 20%by weight, not only the effect of improving the print quality tends tohave peaked, but also an adverse effect of increasing the viscositytends to occur. More preferably, the di(tri)ethylene glycol monobutylether content of the ink falls between 0.5% by weight and 10% by weight.

In case where the ink jet recording ink contains at least 0.5% by weightof the at least one compound selected from the group consisting ofacetylene glycol surfactants and acetylene alcohol surfactants, it isdesirable that the ratio by weight of the compound to thedi(tri)ethylene glycol monobutyl ether is controlled to fall between 1:0and 1:10 for ensuring good print quality. The di(tri)ethylene glycolmonobutyl ether is effective for improving the solubility of theacetylene glycol surfactants and for improving the print quality.However, if the addition amount thereof is over 10 times thedi(tri)ethylene glycol monobutyl ether, those effects tends to havepeaked, and the handling as an ink jet recording ink becomes worsened.

The 1,2-alkylene glycols include 1,2-(C₄₋₁₀ alkyl)diols.

Preferably, the 1,2-(C₄₋₁₀ alkylene) glycol content in the ink is atmost 15% by weight for imparting satisfactory ink penetration suitablefor ink jet recording ink. Of 1,2-alkylene glycols, those in which thenumber of the carbon atoms in the alkylene group is 3 or less give onlya small effect of improving the penetration. On the other hand, those inwhich the number of the carbon atoms is more than 10 are poorly solublein water, and are therefore difficult to be used in water-soluble ink asin the present invention, which necessitates the introduction of astructure added with an oxyethylene chain or a water-soluble group suchas sulfonic acid group or phosphoric acid group. Provided that thenumber of carbon atoms is 4 or more, 1,2-alkylene glycol derivativeshaving such a water-soluble group introduced thereinto and having atmost 30 carbon atoms can be suitably used.

Preferably, the 1,2-(C₄₋₁₀ alkylene) glycol content in the ink is atmost 15% by weight. If it is larger than 15% by weight, not only theeffect of improving the ink penetration tends to have peaked todeteriorate the effect of improving the print quality, but also anadverse effect of increasing the viscosity tends to readily occur.

The 1,2-alkylene glycol includes, for example, 1,2-butanediol (1,2-BD),1,2-pentanediol (1,2-PeD), 1,2-hexanediol (1,2-HD), 1,2-octanediol, and1,2-decanediol. Of those 1,2-alkylene glycols, 1,2-pentanediol and/or1,2-hexanediol are highly effective when used directly as they are.

Particularly preferably, the 1,2-pentanediol content in the ink fallsbetween 3% by weight and 15% by weight. If it is smaller than 3% byweight, the effect of improving the penetration tends to be lowered.Also preferably, the 1,2-hexanediol content in the ink falls between0.5% by weight and 10% by weight. If it is smaller than 0.5% by weight,the effect of improving the penetration tends to be lowered.

Preferably, the ink jet recording ink of the invention further containsat least one compound selected from the group consisting of polyalcoholsand compounds of formula (1) set forth below, thereby the dispersionstability and ejection stability of the ink can be improved.R-EOn-POm-M  (1)wherein R represents a C₄₋₁₂ alkanol, cycloalkanol, phenol and/ornaphthol group, which is linear and/or another isomer; EO represents anethyleneoxy group; PO represents a propyleneoxy group; n and m eachindicate the mean value of the repetitive units in the whole system; theindication of EO and PO merely represent the presence thereof in themolecule, not limiting their order; M represents a hydrogen atom, asulfonate group, a phosphate group and/or a borate group, and thecounter ion of the sulfonate group, the phosphate group and/or theborate group is a hydrogen atom, an alkali metal, an inorganic baseand/or an organic amine.

With regard to M of formula (1) above, the alkali metal includes, forexample, lithium, sodium, and potassium; the inorganic base may beammonia; and the organic amine includes, for example, monoethanolamine,diethanolamine, triethanolamine, monoisopropanolamine, andmono-s-butanolamine.

In formula (1), preferably, n falls between 0 and 10 and m falls between1 and 5. Since m and n each indicate the mean value in the ink system,it is presumed that the molecules of formula (1) have a molecular weightdistribution. However, they may be monodispersed.

Starting from alcohols, the compounds of formula (1) are prepared byadding a target amount of ethylene oxide or propylene oxide to thealcohol in an alkali or the like atmosphere, or by adding thereto any of(mono, di, tri, . . . )propylene glycol or (mono, di, tri, . . .)ethylene glycol through dehydration. In general, therefore, thecompounds are not monodispersed, but there is no problem in making itmonodispersed through an additional process such as distillation or thelike for use herein. However, the residual alcohol content in the ink ispreferably at most 1% by weight. If larger than 1% by weight, itinvolves some problems such that the ink wets the nozzle surface of ahead to readily deteriorate the print quality and that a smell ofalcohol is generated.

Preferably, the mean molecular weight of the compounds of formula (1) isat most 2000. If their mean molecular weight is larger than 2000,adverse effects such as deterioration in penetration effect and anincrease in the ink viscosity are readily caused. More preferably, themean molecular weight is at most 1000, further preferably at most 500.

In case where the ink jet recording ink contains at most 5% by weight ofthe acetylene glycol surfactant, the ratio of the compound of formula(1) to the acetylene glycol surfactant preferably falls between 1:0.1and 1:3 from the view point of print quality. Examples of the acetyleneglycol surfactant include Surfynol series manufactured by Air Products(USA) and Olfin series manufactured by Nisshin Chemical Industry.

Preferably, the addition amount of the compound of formula (1) in theink falls between 0.5% by weight and 30% by weight.

In case where the ink jet recording ink contains at most 10% by weightof (di)propylene monoglycol butyl ether as the glycol ethers, the ratioby weight of the compound of formula (1) to the glycol ether preferablyfalls between 1:0.1 and 1:10.

In case where the ink jet recording ink contains at most 20% by weightof di(tri)ethylene glycol monobutyl ether as the glycol ethers, theratio by weight of the compound of formula (1) to the glycol etherpreferably falls between 1:0.1 and 1:10.

Also preferably, the ratio by weight of the compound of formula (1) tothe 1,2-alkylene glycol in the ink jet recording ink falls between 1:0.1and 1:10.

Also preferably, the polyalcohols are C₃₋₁₂ alkyldiols and/or C₃₋₁₂alkyltriols. Specifically, for example 1,2-propanediol (1,2-PD),1,3-propanediol (1,3-PD), 1,3-butanediol (1,3-BD), 1,4-butanediol(1,4-BD), 2,3-pentanediol (2,3-PeD), 1,5-pentanediol (1,5-PeD),2-methyl-2,4-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, and1,2,6-hexanetriol are on the market.

Also preferably, the ink jet recording ink of the invention furthercontains a saccharide and glycerin. The use of the saccharide andglycerin, which are soluble in water and have an effect of waterretention, in combination, an effect of suppressing the evaporation ofwater is enhanced, to thereby prevent the viscosity increase orsolidification of the ink due to drying up at the nozzle tips of a head.Accordingly, clogging with the ink can be surely prevented (that is, theclogging reliability can be improved), and satisfactory long-termejection stability can be ensured.

The saccharide for use in the invention includes monosaccharides,oligosaccharides, polysaccharides and glycosides.

Including monosaccharides, oligosaccharides, polysaccharides andglycosides, the saccharide may be in any form of aldehydes, ketones orglycoalcohols. Specifically, examples thereof include erythrose,threose, erythrulose, erythritol, arabinose, xylose, ribulose, xylulose,xylitol, glucose, mannose, galactose, talose, fructose, psicose,tagatose, sorbose, sorbitol, mannitol, trehalose, kojibiose, nigrose,maltose, isomaltose, isotrehalose, sophorose, laminaribiose, cellobiose,gentibiose, multidextrin, linear oligosaccharides,isomaltooligosaccharides, isomerized saccharides, gentioligosaccharides,polydextrose, maltitol, fructooligosaccharides, palatinose, palatinoseoligosaccharides, emulsified oligosaccharides, lactitol, lactulose,lactosucrose, galactooligosaccharides, soybean oligosaccharides,xylooligosaccharides, chitin-chitosan oligosaccharides, pectinoligosaccharides, agarooligosaccharides, inulooligosaccharides,paranichit, reduced starch syrup, carrageenan, alginic acid, pullulan,xanthan gum, gellan gum, curdlan, polydextrose and polydextrose. Ofthese saccharides, those having a large molecular weight increase theviscosity of the ink, and hence their amount to be added is limited.Therefore, monosaccharides and disaccharides having a relatively smallmolecular weight are preferred. Addition of the polysaccharide in alarge amount is not preferred since it increases the ink viscosity.

Accordingly, at least 80% by weight of the saccharide added to the inkpreferably comprises aldose, ketose and/or glycoalcohol each having atmost 12 carbon atoms.

Particularly preferred examples of the saccharide for use in theinvention include glucose, mannose, maltitol, fructose, ribose, xylose,arabinose, lactose, galactose, aldonic acid, glucitose, maltose,cellobiose, sucrose, trehalose, erythritol, maltotriose,isomaltooligosaccharides, mannitol, sorbitol, fructose, and xylitol. Inthe invention, the addition amount of the saccharide preferably fallsbetween 0.05% by weight and 30% by weight, more preferably between 3% byweight and 20% by weight. If the amount of the saccharide is smallerthan 0.05% by weight, the effect of recovering from the phenomenon thatthe ink is dried up at the nozzle tip portion of a head to clog thenozzle, i.e., a so-called clogging phenomenon, is small. On the otherhand, if larger than 30% by weight, the viscosity of the ink isincreased to cause a problem in the ejection stability, such as theoccurrence of an ejection defect, etc., thus not being preferred.

Preferably, the ink jet recording ink of the invention containsglycerin, and at least one member selected from saccharides andcompounds of a formula (2) set forth below. Particularly since the colordevelopment of the images can be improved thereby, the print quality canbe further improved. In addition, the ink is more surely prevented fromclogging head nozzles (the clogging reliability can be improved).A-(EP)n  (2)wherein A represents a glycerin skeleton; EP represents an ethyleneoxygroup (terminal OH) and/or a propyleneoxy group (terminal OH), but maybe an OH group; and n indicates the repetitive units.

In formula (2), n preferably falls between 0.5 and 10. If n is smallerthan 0.5, the effect of improving print quality is small and, on theother hand, if larger than 10, an adverse effect such as viscosityincrease is caused. However, in the case where the compound is used incombination with the saccharide described above, n in formula (2) is notlimited to the range, though depending on the addition amount thereof.For example, n may be smaller than 0.5, or may be larger than 10 notexceeding 30.

Preferably, the repetitive units (EP) indicated with n in formula (2)are ethyleneoxy and/or propyleneoxy groups, and the compounds preferablyhave a molecular weight distribution. (EP) is preferably ethyleneoxyand/or propyleneoxy. Particularly, when the ink is desired to have a lowviscosity, ethyleneoxy is preferably used, whereas when the ink isdesired to have a relatively high viscosity, propyleneoxy is preferablyused. The amounts thereof can be appropriately selected. These additivesare preferred since they improve the ejection stability of the ink.

Preferably, the mean molecular weight of the compound of formula (2) isat most 1000. If the mean molecular weight is larger than 1000, itbecomes hard to surely improve the clogging reliability. Regarding thedegree of the molecular weight distribution, it is preferred that theratio of weight-average molecular weight (Mw)/number-average molecularweight (Mn) is at least 1.5, but this does not deny the ratio of smallerthan 1.5.

Preferably, the dye for use in the invention is insoluble or hardlysoluble in water. For use in the colorant in the present invention,examples thereof include, for example, oil-soluble dyes, basic dyes,disperse dyes, vat dyes, sulfide dyes, organic solvent-soluble dyes, andreactive dyes.

The pigment for use in the invention is not particularly limited, andany of inorganic dyes and organic dyes can be used. The inorganic dyesinclude, for example, metallic dyes such as copper oxides, iron oxides,and titanium oxides; and carbon blacks such as furnace black, lampblack, acetylene black, and channel black. The organic pigments include,for example, azo pigments (including azo lakes, insoluble azo pigments,condensed azo pigments, chelate azo pigments), polycyclic pigments(e.g., phthalocyanine pigments, perylene pigments, perinone pigments,anthraquinone pigments, quinacridone pigments, dioxane pigments,thioindigo pigments, isoindolinone pigments, quinofuranone pigments),dye chelates (e.g., basic dye chelates, acid dye chelates), nitropigments, nitroso pigments, and aniline black.

As the pigment for black ink, C.I. Pigment Black 11 which is an ironoxide; C.I. Pigment Black 7 which is a carbon black; and C.I. PigmentBlack 1 which is an aniline black can be mentioned. More specifically,the following carbon blacks can be exemplified: Mitsubishi Chemical'sNo. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8,MA100, No. 2200B; Columbia's Raven 5750, Raven 5250, Raven 5000, Raven3500, Raven 1255, Raven 700; Cabot's Regal 400$, Regal 330R, Regal 660R,Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch1000, Monarch 1100, Monarch 1300, Monarch 1400; Dexxa's Color Black FW1,Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200,Color Black S150, Color Black S160, Color Black S170, Printex 35,Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5,Special Black 4A, Special Black 4.

Examples of the pigment for yellow ink include C.I. Pigment Yellow 1(Fast Yellow G), 2, 3, 12 (Disazo Yellow AAA), 13, 14, 16, 17, 24, 34,35, 37, 42 (yellow iron oxide), 53, 55, 73, 74, 75, 81, 83 (DisazoYellow HR), 93, 95, 97, 98, 100, 101, 104, 108, 109, 110, 114, 117, 120,128, 129, 138, 151, 153 and 154.

Examples of the pigment for magenta ink include C.I. Pigment Red 1, 2,3, 5, 7. 12, 17, 22 (Brilliant Fast Scarlet Red), 23, 31, 38, 48 (Ca),48 (Mn), 48:2 (Permanent Red 2B (Ba)), 48:2 (Permanent Red 2B (Ca)),48:3 (Permanent Red 2B (Sr)), 48:3 (Permanent Red 2B (Mn)); 49:1, 52:2,53:1, 57)Ca), 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81(Rhodamine 6G Lake), 83, 88, 101 (red iron oxide), 104, 105, 106, 108(cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166,168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 209 and 219.

Examples of the pigment for cyan ink include C.I. Pigment Blue 1, 2, 3,15 (Phthalocyanine Blue R), 15:1, 15:2, 15:3 (Phthalocyanine Blue G),15:4, 15:6 (Phthalocyanine Blue E), 15:34, 16, 17:1, 22, 56, 60 and 63,C.I. Vat Blue 4, and C.I. Vat Blue 60.

Examples of the pigment for green ink include C.I. Pigment Green 1, 4,7, 8, 10, 17, 18 and 36.

With regard to the particle size of the pigment, pigments comprisingparticles of at most 0.5 μm are preferred, and pigments comprisingparticles falling between 0.01 and 0.15 μm are more preferred.

The addition amount of the colorant of such pigment and/or dye envelopedin a polymer preferably falls between 0.5% by weight and 30% by weight,more preferably between 1.0% by weight and 12% by weight. If theaddition amount is smaller than 0.5% by weight, printed density tends tobecome hardly ensued. On the other hand, if larger than 30% by weight,there is a tendency that a viscosity increase of the ink or a structuralviscosity in the viscosity characteristics is caused to therebydeteriorate the ejection stability.

In the colorant of the pigment and/or dye enveloped in a polymer, thecontent of the polymer is preferably at least 10% by weight, morepreferably at least 20% by weight, still more preferably at least 30% byweight with respect to the whole amount of the colorant. When thepolymer content is not smaller than 10% by weight, in particular, theproperty of recovering from nozzle clogging becomes good. In case ofcolor inks (e.g., cyan ink, magenta ink, yellow ink, etc.), the colortransparency through transparent sheets such as OHP sheet becomesfurther good.

When the polymer content in the colorant is smaller than 10% by weight,the above-mentioned acetylene alcohol surfactants, acetylene glycolsurfactants, glycol ethers, polyalcohols and substances of formula (2)may partially swell the polymer. In such a case, the polymer readilypeels off from the pigment, sometime resulting in an increase viscosityof the ink.

The colorant of the pigment and/or dye enveloped in a polymer isdescribed in more detail below. The term “enveloping” as used in thepresent invention means that the pigment and/or dye for the colorant iscompletely enveloped in a polymer.

The polymer that envelops the pigment and/or dye therein preferablycomprises, as a main component, at least one member selected from thegroup consisting of vinyl polymers such as polyacrylates,styrene-acrylic acid copolymers, polystyrenes; and polyesters,polyamides, polyimides, silicon-containing polymers andsulfur-containing polymers.

If an ordinary pigment (not enveloped in a polymer) is dispersed inwater by a dispersant, and a compound selected from acetylene glycolsurfactants, acetylene alcohol surfactants, glycol ethers and1,2-alkylene glycols is added to the aqueous dispersion, then thedispersant readily drops off from the pigment surface, and the compoundmay adhere to the pigment in place of the dropped dispersant. As aresult, a phenomenon that the dispersant having dropped off from thepigment disturbs the printing readily occurs. In contrast, where theabove-described polymer is used for enveloping the pigment and/or dyetherein, the polymer can stably envelop the colorant therein, making itdifficult to cause the phenomenon mentioned above. Therefore, the use ofthe colorant of the pigment and/or dye enveloped in the polymer as acolorant of an ink composition makes it possible to attain stableejection and satisfactory images.

In one particularly preferred embodiment of the invention, suitableexamples of the polymer include those prepared by polymerizable monomersor oligomers having a double bond of an acryloyl, methacryloyl, vinyl orallyl group through ordinary polymerization using a polymerizationinitiator.

The monomers include, for example, styrene, tetrahydrofurfuryl acrylate,butyl methacrylate, (α, 2, 3 or 4)-alkylstyrenes, (α, 2, 3 or4)-alkoxystyrenes, 3,4-dimethylstyrene, α-phenylstyrene, divinylbenzene,vinylnaphthalene, dimethylamino (meth)acrylate, dimethylaminoethyl(meth)acrylate, dimethylaminopropylacrylamide, N,N-dimethylaminoethylacrylate, acryloylmorpholine, N,N-dimethylacrylamide,N-isopropylacrylamide, N,N-diethylacrylamide, methyl (meth)acrylate,ethyl (meth)acrylate, propyl (meth)acrylate, ethylhexyl (meth)acrylate,other alkyl (meth)acrylates, methoxydiethylene glycol (meth)acrylate,ethoxy, propoxy or butoxy-having diethylene glycol or polyethyleneglycol (meth)acrylates, cyclohexyl (meth)acrylate, benzyl(meth)acrylate, phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate,hydroxyalkyl (meth)acrylates, fluorine, chlorine or bromine-containing(meth)acrylates, (meth)acrylamides, maleic acid amides; and foradditionally introducing a crosslinked structure to monofunctional(meth)acrylic acids, examples thereof include acryl or methacrylgroup-having compounds such as (mono, di, tri, tetra, polyethyleneglycol di(meth)acrylates, 1,4-butanediol, 1,5-pentanediol,1,6-hexanediol, 1,8-octanediol and 1,10-decanediol (meth)acrylates,trimethylolpropane tri(meth)acrylate, glycerin (di, tri)(meth)acrylates,bisphenol A or bisphenol F-ethylene oxide adduct di(meth)acrylates,neopentyl glycol di(meth)acrylate, pentaerythritol tetra(meth)acrylateand dipentaerythritol hexa(meth)acrylate.

The polymerization initiator may be any ordinary one generally used inradical polymerization, including, for example, potassium persulfate,ammonium persulfate, as well as hydrogen persulfate,azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, peraceticacid, cumemehydroperoxide, t-butylhydroxyperoxide,paramenthanehydroxyperoxide. However, preferred for use herein arewater-soluble polymerization initiators.

Examples of the method for enveloping the pigment and/or dye in such apolymer include phase conversion emulsification, acid deposition andforced emulsification.

One known example of the phase conversion emulsification comprises:dissolving a self-water-dispersible resin (self-water-dispersiblepolymer), in which a part of the acid group is neutralized with a base,in an organic solvent; dispersing or dissolving a pigment and/or dye inthe resulting solution to give a colorant resin solution; and mixing itwith an aqueous medium essentially comprising water, to thereby undergophase conversion emulsification. Upon the phase conversionemulsification, colorant particles in which the pigment and/or dye isenveloped in the resin are generated. Therefore, by subsequentlyremoving the organic solvent from the aqueous medium, a colorantenveloping the pigment and/or dye can be suitably obtained. Preferredexamples of the self-water-dispersible resin include copolymers of atleast one monomer selected from the group consisting of styrene,substituted styrenes and (meth)acrylates, having an acid value of from20 to 200 KOH mg/g, with (meth)acrylic acid.

Another known example of the phase conversion emulsification comprisesadding a polyester to a ketone solvent together with the pigment and/ordye, adding a neutralizing agent to the ketone solution to therebyionize the carboxyl group in the polyester, and adding water thereto toundergo phase conversion emulsification. By evaporating away the ketonesolvent from the mixed solvent, and a colorant enveloping the pigmentand/or dye in a polyester can be suitably obtained.

One example of the acid deposition process comprises adding an acidiccompound to an aqueous dispersion of the pigment and/or dye finelydispersed by a “resin (polymer) having a carboxyl group neutralized witha basic compound” to make the pH of the aqueous dispersion neutral oracidic, thereby making the resin hydrophobic so that the pigment can befirmly fixed onto the resin. By subsequently adding a basic compound tothe aqueous dispersion so as to neutralize again the carboxyl group inthe resin, an aqueous dispersion of a colorant enveloping the pigmentand/or dye in a resin (polymer) can be suitably obtained.

One known example of the forced emulsification process comprises addinga vinyl polymer having a silicon macromer as a copolymerizablecomponent, and the pigment and/or dye to an organic solvent, adding aneutralizing agent to the resulting solution or dispersion to therebyionize the salt-forming group in the vinyl polymer, and adding waterthereto to emulsify it. By subsequently evaporating away the organicsolvent, a colorant enveloping the pigment and/or dye in the polymer canbe suitably obtained.

The polymer that envelops pigment and/or dye therein is typically acopolymer of a polymerizable group-having dispersant and acopolymerizable monomer, which will be described in detail below. Thecolorant of the pigment and/or dye enveloped in such a copolymer of apolymerizable group-having dispersant and a copolymerizable monomer canbe suitably obtained by dispersing the pigment and/or dye in water by apolymerizable group-having dispersant, followed by adding acopolymerizable monomer and a polymerization initiator thereto toundergo polymerization.

It is preferred that the particles in the ink jet recording ink have arelatively uniform particle size from the views points of clogging andejection stability. Therefore, the colorant of the pigment and/or dyeenveloped in the polymer is preferably prepared through emulsionpolymerization.

In case where a pigment is used, the pigment colorant enveloped in apolymer is preferably prepared by dispersing the pigment in water by apolymerizable group-having dispersant followed by conducting emulsionpolymerization in water using a monomer copolymerizable with thedispersant (copolymerizable monomer) and a polymerization initiator.

The colorant of the dye enveloped in a polymer is preferably prepared bydirectly dissolving a water-insoluble or hardly water-soluble dye suchas oil-soluble dye, disperse dye, vat dye or reactive dye in a monomer,followed by conducting emulsion polymerization.

The emulsion polymerization may be effected in any ordinary manner, andthe polymerization is proceeded with free radicals that are formedthrough thermal decomposition of a water-soluble polymerizationinitiator in the presence of an emulsifier.

The copolymerizable monomer is preferably a compound having anunsaturated group in its structure. The unsaturated group is preferablyselected from the group consisting of a vinyl group, an allyl group, anacryloyl group, a methacryloyl group, a propenyl group, an acrylamidogroup, a vinylamido group, a vinylidene group and a vinyl group.

More specifically, the copolymerizable monomer is may be any of thosehaving high copolymerizability with a polymerizable group-havingdispersant, and commonly used radically polymerizable monomers can beused therefor. Examples of the radically polymerizable monomer includethose containing, in its molecule, at least one radically polymerizableunsaturated hydrocarbon group such as vinyl, allyl, acryloyl ormethacryloyl, propenyl, acrylamido, vinylamido, vinylidene and vinylenegroups. Specific examples of the radically polymerizable monomer includestyrene and styrene derivatives such as methylstyrene, dimethylstyrene,chlorostyrene, dichlorostyrene, bromostyrene, p-chloromethylstyrene,divinylbenzene; acrylic acid and mono-functional acrylates such asmethyl acrylate, ethyl acrylate, n-butyl acrylate, butoxyethyl acrylate,benzyl acrylate, phenyl acrylate, phenoxyethyl acrylate, cyclohexylacrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate,dicyclopentenyloxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornylacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,2-acryloyloxyethyl succinate, 2-acryloyloxyethyl phthalate, caprolactoneacrylate, glycidyl acrylate; methacrylic acid and monofunctionalmethacrylates such as methyl methacrylate, ethyl methacrylate, n-butylmethacrylate, 2-ethylhexyl methacrylate, butoxymethyl methacrylate,benzyl methacrylate, phenyl methacrylate, phenoxyethyl methacrylate,cyclohexyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenylmethacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofurfurylmethacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate,2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, glycerolmethacrylate, 2-methacryloyloxyethyl succinate, 2-methacryloyloxyethylphthalate, caprolactone methacrylate, glycidyl methacrylate; allylcompounds such as aminoethyl acrylate, aminopropyl acrylate,methylaminoethyl acrylate, methylaminopropyl acrylate, ethylaminoethylacrylate, ethylaminopropyl acrylate, acrylic aminoethylamide, acrylicaminopropylamide, acrylic methylaminoethylamide, acrylicmethylaminopropylamide, acrylic ethylaminoethylamide, acrylicethylaminopropylamide, methacrylic amide, aminoethyl methacrylate,aminopropyl methacrylate, methylaminoethyl methacrylate,methylaminopropyl methacrylate, ethylaminoethyl methacrylate,ethylaminopropyl methacrylate, methacrylic aminoethylamide, methacrylicaminopropylamide, methacrylic methylaminoethylamide, methacrylicmethylaminopropylamide, methacrylic ethylaminoethylamide, methacrylicethylaminopropylamide, hydroxymethyl acrylate, hydroxymethylmethacrylate, N-methylolacrylamide, allyl alcohol, allylbenzene, allyl3-cyclohexanepropionate, 1-allyl-3,4-dimethoxybenzene, allylphenoxyacetate, allyl phenylacetate, allylcyclohexane, and allyl estersof polycarboxylic acids; fumaric acid, maleic acid, itaconic acid, andtheir esters; and other radically polymerizable group-having monomerssuch as acrylonitrile, methacrylonitrile, maleic anhydride,N-substituted maleimides, and cyclic olefins.

In particular, monomers having a hydrophilic group is preferably used asthe copolymerizable monomer. Examples of a carboxyl group-having monomerinclude, for example, acrylic acid, methacrylic acid, crotonic acid,ethacrylic acid, propylacrylic acid, isopropylacrylic acid,2-acryloyloxyethylsuccinic acid, 2-acryloyloxyethylphthalic acid,2-methacryloyloxyethylsuccinic acid, 2-methacryloyloxyethylphthalicacid, itaconic acid, fumaric acid, and maleic acid. Of these, preferredare acrylic acid and methacrylic acid. Examples of a sulfonic acidgroup-having monomer include, for example, 4-methylsulfonic acid and itssalts, vinylsulfonic acid and its salts, sulfoethyl acrylate and itssalts, sulfoethyl methacrylate and its salts, sulfoalkyl acrylates andtheir salts, sulfoalkyl methacrylates and their salts, sulfopropylacrylate and its salts, sulfopropyl methacrylate and its salts,sulfoaryl acrylates and their salts, sulfoaryl methacrylates and theirsalts, butylacrylamidosulfonic acid and its salts,2-acrylamido-2-methylpropanesulfonic acid and its salts. Examples of ahydroxyl group-having monomer include, for example, 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutylmethacrylate, polyethylene glycol 400 acrylate, polyethylene glycol 400methacrylate, N-hydroxyethyl acrylate, and N-hydroxyethyl methacrylate.Examples of an amido group-having monomer include, for example,acrylamide, methacrylamide, acrylic aminopropylamide, methacrylicaminoproylamide, acrylic aminoethylamide, methacrylic aminoethylamide,and vinylpyrrolidone. Examples of a phosphone group-having monomerinclude phosphoethyl methacrylate.

Polymerizable surfactants of formula (I) (mentioned in detail below)that are preferred for the polymerizable group-having dispersant aremonomers of high electron donating ability. Therefore, thecopolymerizable monomers to be used are preferably those of highelectron acceptability. Examples of the copolymerizable monomer of highelectron acceptability include acrylonitrile, fumaronitrile, fumaricdiesters such as dibutyl fumarate; maleic diesters such as dibutylmaleate; maleimides such as N-phenylmaleimide; and vinylidene cyanide.These may be used singly or as a mixture of two of more thereof.

The addition amount of the copolymerizable monomer preferably fallsbetween around 2 and 15 times, more preferably between around 3 and 12times, in terms of molar ratio with respect to the polymerizablegroup-having dispersant. With a molar ratio of at least 2 times thedispersant, the encapsulated pigment particles formed have excellentdispersion stability in an aqueous medium. With a molar ratio of at most15 times the dispersant, the monomer can be sufficiently dissolved inthe adsorbing layer of the polymerizable group-having dispersant tosuppress the formation of water-insoluble polymers and the relativereduction in the amount of ionic repulsive groups, thereby making itpossible to enhance the dispersion stability.

Suitable examples of the polymerization initiator to be used inpreparing the copolymer of the polymerizable group-having dispersant andthe copolymerizable monomer include potassium persulfate, ammoniumpersulfate, sodium persulfate, 2,2-azobis(2-methylpropionamidine)dihydrochloride, and 4,4-azobis(4-cyanovaleric acid).

In the emulsion polymerization, a chain transfer agent can be also used.Examples thereof include t-dodecylmercaptan, as well asn-dodecylmercaptan, n-octylmercaptan, xanthogens such asdimethylxanthogen disulfide, diisobutylxanthogen disulfide; anddipentene, indene, 1,4-cyclohexadiene, dihydrofuran, and xanthene.

For dispersing the pigment and/or dye in water, for example, employableare dispersion methods with ultrasonic waves, or in bead mills, sandmills or roll mills. In particular, in the case where a pigment is used,the use of a disperser such as bead mill, sand mill or roll mill ispreferred, since the pigment colorant can be formed into fine particlesthereby.

The polymer that envelops the pigment and/or dye therein include apolymer having a crosslinked structure.

The colorant of the pigment and/or dye enveloped in such a crosslinkedstructure-having polymer for use in the invention may be preparedthrough phase conversion emulsification of the pigment and/or dye with apolymer having a crosslinking reactive group and a hydrophilic group tothereby make the pigment and/or dye enveloped in the polymer, followedby crosslinking reaction with a crosslinking agent.

Specifically, the “pigment and/or dye”, the polymer having acrosslinking reactive group and a hydrophilic group, and a crosslinkingagent are added to an organic solvent to prepare a solution ordispersion, to which are added a neutralizing agent and optionally asurfactant (this surfactant is preferably a polymerizable surfactantdescribed in detail below), to obtain the resulting mixture as anorganic solvent phase. While either of the organic solvent phase orwater is stirred, water is put into the organic solvent phase or theorganic solvent phase is put into water to undergo phase conversionemulsification, thereby enveloping the “pigment and/or dye” in theorganic phase that comprises the polymer having a crosslinking reactivegroup and a hydrophilic group and the crosslinking agent. In thisprocess, a catalyst to initiate the crosslinking reaction may be addedto either the organic solvent phase or the aqueous phase. When thecatalyst is soluble in oil, it is preferably added to the organicsolvent phase; but when soluble in water, it is preferably added to theaqueous phase. Next, the polymer is crosslinked at a predeterminedtemperature, at which crosslinking reaction takes place, for apredetermined period of time, and then the organic solvent is evaporatedaway by a general method of, for example, ordinary distillation orreduced pressure distillation, to thereby obtain an aqueous dispersionin which the colorant of a coloring material enveloped in a polymerhaving a crosslinked structure is dispersed.

The polymer having a crosslinking reactive group and a hydrophilic groupis not particularly limited so long as it has at least a crosslinkingreactive group and a hydrophilic group. Examples thereof include, forexample, vinyl polymers, polyacrylates, styrene-acrylic acid copolymers,polyesters, polyamides, polyimides, polyurethanes, amino polymers,silicon-containing polymers, sulfur-containing polymers,fluorine-containing polymers, epoxy resins and their mixtures, having acrosslinking reactive group and a hydrophilic group.

The hydrophilic group of the polymer having a crosslinking reactivegroup and a hydrophilic group includes a sulfone group, a sulfonic acidgroup, a carboxyl group, a hydroxyl group and their salts and quaternaryammonium salts, and is preferably selected therefrom.

The crosslinking reactive group of the polymer having a crosslinkingreactive group and a hydrophilic group includes a glycidyl group, anisocyanate group, a hydroxyl group, a carboxyl group and an unsaturatedhydrocarbon group, and is preferably selected therefrom.

The unsaturated hydrocarbon group of the polymer having a crosslinkingreactive group and a hydrophilic group includes a vinyl group, an allylgroup, an acryloyl group, a methacryloyl group, a propenyl group, avinylidene group and a vinylene group, and is preferably selectedtherefrom.

In one preferred embodiment of the invention, vinyl polymers,poly(meth)acrylates, and styrene-(meth)acrylic acid copolymers are usedfor the polymer having a crosslinking reactive group and a hydrophilicgroup. These polymers may be prepared by polymerizing: a (meth)acrylatemonomer having at least one hydrophilic group selected from the groupconsisting of a sulfone group, a sulfonic acid group, a carboxyl group,a hydroxyl group and their salts and quaternary ammonium salts; a(meth)acrylate monomer having a crosslinking reactive group such as aglycidyl group or an isocyanate group; and a monomer capable ofcopolymerizable with these monomers, in a mode of solutionpolymerization in an solvent such as an aliphatic hydrocarbon solvent,an aromatic hydrocarbon solvent, an ester solvent, a ketone solvent, analcohol solvent or an aprotic solvent, in the presence of apolymerization initiator of, for example, peroxides such as t-butylperoxybenzoate, di-t-butyl peroxide, cumene perhydroxide, acetylperoxide, benzoyl peroxide or lauroyl peroxide, or azo compounds such asazobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile orazobiscyclohexanecarbonitrile. Upon the solution polymerization,optionally added is a polymer chain transfer agent, examples of whichincludes, for example, mercaptans such as octylmercaptan,n-dodecylmercaptan, t-dodecylmercaptan, n-hexadecylmercaptan,n-tetradecylmercaptan, t-tetradecylmercaptan; xanthogen disulfides suchas dimethylxanthogen disulfide, diethylxanthogen disulfide,diisopropylxanthogen disulfide; thiuram disulfides such astetramethylthiuram disulfide, tetraethylthiuram disulfide,tetrabutylthiuram disulfide; halogenohydrocarbons such as carbontetrachloride, ethylene bromide; hydrocarbons such as pentaphenylethane;acrolein, methacrolein, allyl alcohol, 2-ethylhexyl thioglycolate,terbinolene, α-terpinene, γ-terpinene, dipentene, α-methylstyrene dimer(preferably containing at least 50 parts by weight of2,4-diphenyl-4-methyl-1-pentene); unsaturated cyclic hydrocarboncompounds such as 9,10-dihydroanthracene, 1,4-dihydronaphthalene,indene, 1,4-cyclohexadiene; unsaturated heterocyclic compounds such asxanthene, 2,5-dihydrofuran. These may be used singly or as a mixture oftwo or more thereof.

The polymerization may be effected generally at 30 to 100° C.,preferably at 50 to 80° C., for 1 to 10 hours. The polymerizationcondition may be appropriately determined, depending on the kinds of theradical polymerization initiator, monomers and solvent to be used.Preferably, the polymerization is effected in an inert gas atmospheresuch as nitrogen. After thus polymerized, the copolymer may be isolatedfrom the reaction mixture in any known method of, for example,reprecipitation or solvent evaporation. The thus-obtained copolymer maybe purified by removing the unreacted monomer and the like throughrepeated reprecipitation, membrane separation, chromatography orextraction. The weight-average molecular weight of the thus-obtainedpolymer preferably falls between 1000 and 50000, more preferably between1000 and 30000, from the view point of easiness of enveloping thecoloring material and easiness of crosslinking.

Of the hydrophilic group-having (meth)acrylate monomers, examples of acarboxyl group-having acrylic monomer include, for example, acrylicacid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylicacid, isopropylacrylic acid, itaconic acid, and fumaric acid. Of those,preferred are acrylic acid and methacrylic acid. Examples of a sulfonicacid group-having (meth)acrylic monomer include, for example, sulfoethylmethacrylate, butylacrylamidosulfonic acid, and2-acrylamido-2-methylpropanesulfonic acid. Examples of a phosphonegroup-having (meth)acrylic monomer include, for example, phosphoethylmethacrylate.

Examples of a crosslinking reactive group-having (meth)acrylate monomerinclude, for example, blocked isocyanate group-having polymerizablemonomers, epoxy group-having monomers, and 1,3-dioxolan-2-on-4-ylgroup-having monomers. The blocked isocyanate group-having polymerizablemonomers may be readily prepared, for example, by reacting an isocyanategroup-having polymerizable monomer such as 2-methacryloyloxyethylisocyanate with a known blocking agent in a mode of addition reaction.Alternatively, they may also be prepared by reacting a vinyl copolymerhaving a hydroxyl group and a carboxyl group with a compound having anisocyanate group and a blocked isocyanate group in a mode of additionreaction. Examples of the epoxy group-having monomer include, forexample, glycidyl (meth)acrylate, and alicyclic epoxy group-having(meth)acrylate monomers. Examples of the 1,3-dioxolan-2-on-4-ylgroup-having monomer include, for example, 1,3-dioxolan-2-on-4-ylmethyl(meth)acrylate, and 1,3-dioxolan-2-on-4-ylmethyl vinyl ether.

The monomer copolymerizable with these monomers includes, for example,(meth)acrylates such as methyl acrylate, ethyl acrylate, isopropylacrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate,2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, benzylacrylate, methyl methacrylate, ethyl methacrylate, isopropylmethacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, n-octylmethacrylate, lauryl methacrylate, stearyl methacrylate, tridecylmethacrylate, benzyl methacrylate; adducts of oil-fatty acids andoxirane structure-having (meth)acrylate monomers, such as adduct ofstearic acid and glycidyl methacrylate; adducts of oxirane compoundswith an alkyl group having at least 3 carbon atoms, and (meth)acrylicacid; styrene monomers such as styrene, α-methylstyrene,o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene;itaconates such as benzyl itaconate, ethyl itaconate; maleates such asdimethyl maleate, diethyl maleate; fumarates such as dimethyl fumarate,diethyl fumarate; and acrylonitrile, methacrylonitrile, vinyl acetate,isobornyl acrylate, isobornyl methacrylate, aminoethyl acrylate,aminopropyl acrylate, methylaminoethyl acrylate, methylaminopropylacrylate, ethylaminoethyl acrylate, ethylaminopropyl acrylate, acrylicaminoethylamide, acrylic aminopropylamide, acrylicmethylaminoethylamide, acrylic methylaminopropylamide, acrylicethylaminoethylamide, acrylic ethylaminopropylamide, methacrylic amide,aminoethyl methacrylate, aminopropyl methacrylate, methylaminoethylmethacrylate, methylaminopropyl methacrylate, ethylaminoethylmethacrylate, ethylaminopropyl methacrylate, methacrylicaminoethylamide, methacrylic aminopropylamide, methacrylicmethylaminoethylamide, methacrylic methylaminopropylamide, methacrylicethylaminoethylamide, methacrylic ethylaminopropylamide, hydroxymethylacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylmethacrylate, N-methylolacrylamide, allyl alcohol.

As the crosslinking agent, those which react with the crosslinkingreactive group of the polymer having a crosslinking reactive group and ahydrophilic group to undergo crosslinking and which have, in itsmolecular structure, at least two functional groups capable of reactingwith the crosslinking reactive group of the polymer can be used. In casewhere the crosslinking reactive group of the polymer is a glycidylgroup, preferably used is a compound having at least two functionalgroups of at least one kind selected from an amino group, a carboxylgroup, a hydroxyl group, an N-methylol group and an N-methylol ethergroup. Examples thereof include, for example, aliphatic amines such asethyleneamines, N-aminoethylpiperazine, metaxylenediamine,1,3-bis(aminomethyl)cyclohexane, polyamides; cycloaliphatic amines suchas paramenthanediamine, mesophoronediamine,bis(4-amino-3-methylcyclohexyl)methane, 2-ethyl-4-methylimidazole;aromatic amines such as metaphenylenediamine, 4,4′-diaminodiphenylamine,4,4′-diaminodiphenylsulfone, dicyanediamide; and acid anhydrides such asphthalic anhydride, pyromellitic anhydride, nadic anhydride. In casewhere the crosslinking reactive group of the polymer having acrosslinking reactive group and a hydrophilic group is an isocyanategroup, preferably used is a compound having at least two functionalgroups of at least one kind selected from a carboxyl group, a hydroxylgroup, an amino group and a mercapto group. Examples thereof include,for example, polyols such as polyether polyols, polytetramethylene etherglycols, alkyleneoxide copolyols, epoxy resin-modified polyols,lactone-polyester polyols, condensed polyester polyols, polycarbonatediols, acrylic polyols, polybutadiene polyols, phosphorus-containingpolyols, halogen-containing polyols; polyamines such as polyetherpolyamines, polytetramethylene-ether diamines, alkyleneoxidecopolyamines, epoxy-modified polyamines, condensed polyester polyamines,polycarbonate polyamines, acrylic polyamines; and polythiols such aspolyether polythiols, polytetramethylene-ether diols, alkyleneoxidecopolythiols, epoxy resin-modified polythiols, lactone-polyesterpolythiols, condensed polyester polythiols, polycarbonate dithiols,acrylic polythiols, polybutadiene polythiols, phosphorus-containingpolythiols, halogen-containing polythiols. In case where thecrosslinking reactive group of the polymer is a hydroxyl group,preferably used is a compound having at least two functional groups ofat least one kind selected from a glycidyl group and an isocyanategroup. In case where the crosslinking reactive group of the polymer isan unsaturated hydrocarbon group, preferably used is a compound havingat least two unsaturated hydrocarbon groups of at least one kindselected from a vinyl group, an allyl group, an acryloyl group, amethacryloyl group, a propenyl group, a vinylidene group, and a vinylenegroup. Examples thereof include, for example, ethylene glycoldiacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate,tetraethylene glycol diacrylate, polyethylene glycol diacrylate, allylacrylate, bis(acryloxyethyl)hydroxyethyl isocyanurate,bis(acryloxyneopentylglycol) adipate, 1,3-butylene glycol diacrylate,1,6-hexanediol diacrylate, neopentylglycol diacrylate, propylene glycoldiacrylate, polypropylene glycol diacrylate,2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxy)phenyl]propane,2,2-bis[4-(acryloxyethoxy)phenyl]propane,2,2-bis[4-(acryloxyethoxy.diethoxy)phenyl]propane,2,2-bis[4-(acryloxyethoxy.polyethoxy)phenyl]propane, hydroxypivalicneopentylglycol diacrylate, 1,4-butanediol diacrylate, dicyclopentanyldiacrylate, dipentaerythritol hexaacrylate, dipentaerythritolmonohydroxypentaacrylate, ditrimethylolpropane tetraacrylate,pentaerythritol triacrylate, tetrabromobisphenol A diacrylate,triglycerol diacrylate, trimethylolpropane triacrylate,tris(acryloxyethyl) isocyanurate, ethylene glycol dimethacrylate,diethylene glycol dimethacrylate, triethylene glycol dimethacrylate,tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,propylene glycol dimethacrylate, polypropylene glycol dimethacrylate,1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate,1,6-hexanediol dimethacrylate, neopentylglycol dimethacrylate,2-hydroxy-1,3-dimethacryloxypropane,2,2-bis[4-(methacryloxy)phenyl]propane,2,2-bis[4-(methacryloxyethoxy)phenyl]propane,2,2-bis[4-(methacryloxyethoxydiethoxy)phenyl]propane,2,2-bis[4-(methacryloxyethoxypolyethoxy)phenyl]propane,tetrabromobisphenol A dimethacrylate, dicyclopentanyl dimethacrylate,dipentaerythritol hexamethacrylate, glycerol dimethacrylate,hydroxypivalic neopentylglycol dimethacrylate, dipentaerythritolmonohydroxypentamethacrylate, ditrimethylolpropane tetramethacrylate,pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate,triglycerol dimethacrylate, trimethylolpropane trimethacrylate,tris(methacryloxyethyl) isocyanurate, allyl methacrylate,divinylbenzene, diallyl phthalate, diallyl terephthalate, diallylisophthalate, and diethylene glycol bisallylcarbonate.

Preferably, the crosslinking agent is added to the organic solvent phasein a ratio by weight falling between 0.01 and 0.1 with respect to thepolymer having a crosslinking reactive group and a hydrophilic group.When the ratio is smaller than 0.01, a viscosity increase with time,nozzle clogging, an ejection stability defect, etc. take place, thus notbeing preferred. On the other hand, when the ratio is larger than 0.1,deterioration in the rubbing resistance, enlargement of the particlesize, etc. take place, thus not being preferred.

The catalyst to be used in the crosslinking reaction is not particularlylimited so long as it has an effect of initiating or promoting thereaction. In case where the crosslinking reactive group of the polymeris an unsaturated hydrocarbon group and the crosslinking agent is acompound having at least two unsaturated hydrocarbon groups of at leastone kind selected from a vinyl group, an allyl group, an acryloyl group,a methacryloyl group, a propenyl group, a vinylidene group and avinylene group, usable are any of oil-soluble radical-polymerizationinitiators, for example, peroxides such as t-butyl peroxybenzoate,di-t-butyl peroxide, cumene perhydroxide, acetyl peroxide, benzoylperoxide, lauroyl peroxide and azo compounds such asazobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile,azobiscyclohexanecarbonitrile; and also water-solubleradical-polymerization initiators such as potassium persulfate, ammoniumpersulfate, sodium persulfate, 2,2-azobis(2-methylpropionamidine)dihydrochloride, and 4,4-azobis(4-cyanovaleric acid). The additionamount of the catalyst may be appropriately determined.

The organic solvent for use in the organic solvent phase is notparticularly limited, so long as it can dissolve the polymer having acrosslinking reactive group and a hydrophilic group. Preferred arelow-boiling-point organic solvents, considering the easiness ofevaporating away. Examples thereof include, for example, ketone-typeorganic solvents such as acetone, methyl ethyl ketone; ester-typeorganic solvents such as ethyl acetate; alcohol-type organic solventssuch as ethanol, isopropyl alcohol; and aromatic hydrocarbon-typeorganic solvents such as benzene.

The ratio by weight of the polymer having a crosslinking reactive groupand a hydrophilic group with respect to the pigment and/or dye can beappropriately determined within the range between 0.3 and 1.5.Preferably, it is so determined that the mean particle size of thecolorant particles be at most 400 nm, more preferably at most 200 nm,and the amount of the water-soluble substance that results from thepolymer having a crosslinking reactive group and a hydrophilic group inthe aqueous phase after production be at most 1000 ppm.

The mixed solution that contains at least the “polymer having acrosslinking reactive group and a hydrophilic group”, the “crosslinkingagent” and the “pigment and/or dye” in an organic solvent may beprepared, for example, according to a method of dispersing the pigmentand/or dye in an organic solvent that contains the polymer having acrosslinking reactive group and a hydrophilic group dissolved therein bythe use of a various disperser such as a bead mill, a roll mill or asand mill, followed by dissolving a crosslinking agent and optionally anoil-soluble catalyst therein; or a method of flushing and dispersing anaqueous dispersion of the pigment and/or dye (for example, a wet cake ofthe pigment) in the polymer having a crosslinking reactive group and ahydrophilic group by the use of a various disperser, followed bydissolving or dispersing a crosslinking agent and optionally anoil-soluble catalyst therein. For improving the pigment dispersion,generally employed are dispersants and surfactants. In the invention,preferably used is a reactive surfactant for that purpose. The reactivesurfactant referred to herein is the same as the polymerizablesurfactant described below. As the reactive surfactant, those capable ofreacting with the polymer having a crosslinking reactive group and ahydrophilic group or with the crosslinking agent can be used. The use ofthe reactive surfactant improves defects likely accompanied with the useof ordinary ink compositions which are prepared by the use of anordinary dispersant or surfactant, such as deterioration in the printedimages, e.g., occurrence of bleeding on plain paper, and an ejectiondefect due to the wetting at the periphery of the nozzles of a printerhead.

For dispersing the colorant into fine particles, it is desirable thatthe phase conversion emulsification is carried out while applyingultrasonic waves.

Another preferred embodiment of the crosslinked structure-having polymeris a copolymer of at least a polymerizable group-having dispersant and acrosslinking monomer.

Naturally, the crosslinked structure-having polymer encompasses polymersprepared through copolymerization of a polymerizable group-havingdispersant, a crosslinking monomer and a monomer copolymerizable withthese crosslinking monomers.

The colorant of pigment and/or dye enveloped in the crosslinkedstructure-having copolymer of at least a polymerizable group-havingdispersant and a crosslinking monomer is meant to indicate completelyencapsulated, fine and stable particles of the pigment and/or dye.

The colorant of the pigment and/or dye enveloped in the crosslinkedstructure-having copolymer of such a polymerizable group-havingdispersant and a crosslinking monomer has excellent dispersion stabilityin various aqueous media comprising a various water-soluble organicsolvent and water. In particular, it has good dispersion stability inthe aqueous media used in the invention that comprise a compoundselected from acetylene glycol surfactants and acetylene alcoholsurfactants, a compound selected from glycol ethers and 1,2-alkyleneglycols, and water. The reason therefor has not yet been clarified, itcan be attributed to that the colorant particles are encapsulated as inthe manner mentioned above, and therefore, as compared with the casewhere a dispersant is adsorbed on the coloring material surfaces by amere Van der Waals force, the enveloping polymer adheres thereto morefirmly by the action of the coloring material, and that the polymer hasa crosslinked structure to thereby improve the solvent resistance. Thistheory is referred to herein merely for explaining the contents of theinvention, which, therefore, should not whatsoever restrict the scope ofthe invention.

The crosslinking monomer for use in the invention is not particularlylimited, so long as it has high copolymerizability with thepolymerizable group-having dispersant.

The crosslinking monomer for use in the invention is preferably acompound having at lest two unsaturated hydrocarbon groups of at leastone kind selected from a vinyl group, an allyl group, an acryloyl group,a methacryloyl group, a propenyl group, a vinylidene group and avinylene group. Examples thereof include, for example, ethylene glycoldiacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate,tetraethylene glycol diacrylate, polyethylene glycol diacrylate, allylacrylate, bis(acryloxyethyl)hydroxyethyl isocyanurate,bis(acryloxyneopentylglycol) adipate, 1,3-butylene glycol diacrylate,1,6-hexanediol diacrylate, neopentylglycol diacrylate, propylene glycoldiacrylate, polypropylene glycol diacrylate,2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxy)phenyl]propane,2,2-bis[4-(acryloxyethoxy)phenyl]propane,2,2-bis[4-(acryloxyethoxy.diethoxy)phenyl]propane,2,2-bis[4-(acryloxyethoxy.polyethoxy)phenyl]propane, hydroxypivalicneopentylglycol diacrylate, 1,4-butanediol diacrylate, dicyclopentanyldiacrylate, dipentaerythritol hexaacrylate, dipentaerythritolmonohydroxypentaacrylate, ditrimethylolpropane tetraacrylate,pentaerythritol triacrylate, tetrabromobisphenol A diacrylate,triglycerol diacrylate, trimethylolpropane triacrylate,tris(acryloxyethyl) isocyanurate, ethylene glycol dimethacrylate,diethylene glycol dimethacrylate, triethylene glycol dimethacrylate,tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,propylene glycol dimethacrylate, polypropylene glycol dimethacrylate,1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate,1,6-hexanediol dimethacrylate, neopentylglycol dimethacrylate,2-hydroxy-1,3-dimethacryloxypropane,2,2-bis[4-(methacryloxy)phenyl]propane,2,2-bis[4-(methacryloxyethoxy)phenyl]propane,2,2-bis[4-(methacryloxyethoxydiethoxy)phenyl]propane,2,2-bis[4-(methacryloxyethoxypolyethoxy)phenyl]propane,tetrabromobisphenol A dimethacrylate, dicyclopentanyl dimethacrylate,dipentaerythritol hexamethacrylate, glycerol dimethacrylate,hydroxypivalic neopentylglycol dimethacrylate, dipentaerythritolmonohydroxypentamethacrylate, ditrimethylolpropane tetramethacrylate,pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate,triglycerol dimethacrylate, trimethylolpropane trimethacrylate,tris(methacryloxyethyl) isocyanurate, allyl methacrylate,divinylbenzene, diallyl phthalate, diallyl terephthalate, diallylisophthalate, and diethylene glycol bisallylcarbonate.

The addition amount of the crosslinking monomer preferably falls between0.1 and 20% by weight, more preferably between 0.1 and 10% by weight ofthe polymer to be obtained. If the addition amount is smaller than 0.1%by weight, viscosity increase with time, nozzle clogging, an ejectionstability defect, etc. take place, thus not being preferred. On theother hand, if it is larger than 20% by weight, an objective colorant ishardly obtained, thus being not preferred.

As the monomer copolymerizable with the polymerizable group-havingdispersant and the crosslinking monomer, commonly used radicallypolymerizable monomers can be used. The radically polymerizable monomerinclude monomers having, in their molecules, at least one radicallypolymerizable unsaturated hydrocarbon group, such as vinyl, allyl,acryloyl, methacryloyl, propenyl, vinylidene and vinylene groups.Examples of the radically polymerizable monomer include styrene andstyrene derivatives such as methylstyrene, dimethylstyrene,chlorostyrene, dichlorostyrene, bromostyrene, p-chloromethylstyrene,divinylbenzene; acrylic acid and mono-functional acrylates such asmethyl acrylate, ethyl acrylate, n-butyl acrylate, butoxyethyl acrylate,benzyl acrylate, phenyl acrylate, phenoxyethyl acrylate, cyclohexylacrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate,dicyclopentenyloxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornylacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,2-acryloyloxyethyl succinate, 2-acryloyloxyethyl phthalate, caprolactoneacrylate, glycidyl acrylate; methacrylic acid and monofunctionalmethacrylates such as methyl methacrylate, ethyl methacrylate, n-butylmethacrylate, 2-ethylhexyl methacrylate, butoxymethyl methacrylate,benzyl methacrylate, phenyl methacrylate, phenoxyethyl methacrylate,cyclohexyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenylmethacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofurfurylmethacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate,2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, glycerolmethacrylate, 2-methacryloyloxyethyl succinate, 2-methacryloyloxyethylphthalate, caprolactone methacrylate, glycidyl methacrylate; allylcompounds such as allylbenzene, allyl-3-cyclohexane propionate,1-allyl-3,4-dimethoxybenzene, allyl phenoxyacetate, allyl phenylacetate,allylcyclohexane, and allyl esters of polycarboxylic acids; fumaricacid, maleic acid, itaconic acid, and their esters; and other radicallypolymerizable group-having monomers such as acrylonitrile,methacrylonitrile, maleic anhydride, N-substituted maleimides, andcyclic olefins.

Polymerizable surfactants of formula (I) (described in detail below)that are preferred for the polymerizable group-having dispersant aremonomers of high electron donating ability. Therefore, the monomers tobe used herein are preferably those of high electron acceptability.Examples of monomers of high electron acceptability includeacrylonitrile, fumaronitrile, fumaric diesters such as dibutyl fumarate;maleic diesters such as dibutyl maleate; maleimides such asN-phenylmaleimide; and vinylidene cyanide. These may be used singly oras a mixture of two or more thereof.

The addition amount of the monomer preferably falls between around 2 and15 times, more preferably between around 3 and 12 times, in terms of themolar ratio with respect to the polymerizable group-having dispersant.With a molar ratio of at least 2 times the dispersant, the colorant(encapsulated colorant particles) formed has excellent dispersionstability in aqueous media. With a molar ratio of at most 15 times thedispersant, the monomer can be sufficiently dissolved in the adsorbinglayer of the polymerizable group-having dispersant to suppress theformation of water-insoluble polymers and the relative reduction in theamount of ionic repulsive groups, thereby making it possible to enhancethe dispersion stability.

The colorant of the pigment enveloped in the crosslinkedstructure-having polymer that is constituted by a polymerizablegroup-having dispersant, a crosslinking monomer and a monomercopolymerizable with these monomers may be prepared in the manner setforth below.

A pigment and/or dye, and a polymerizable group-having dispersant areadded to an aqueous organic solvent and/or water, and wet-ground in adisperser such as an ultrasonic disperser, a ball mill or a sandgrinder, and then transferred into a reactor equipped with an ultrasonicgenerator, a stirrer, a dropping unit, a reflux condenser, a thermometerand a temperature controller. To this are added a crosslinking monomer,another copolymerizable monomer, a polymerization initiator andoptionally water and/or an aqueous organic solvent, and they are allowedto undergo polymerization reaction at 40 to 100° C. for 10 to 60 hoursto give a colorant of a pigment and/or dye enveloped in a crosslinkedstructure-having polymer. The addition amount of the polymerizationinitiator preferably falls between 0.1 and 5% by weight, more preferablybetween 0.1 and 3% by weight with respect to the total amount of thepolymerizable group-having dispersant, the crosslinking monomer and thecopolymerizable monomer. More preferably, the preparation can be carriedout according to the method described in Japanese Patent Laid-Open No.316909/1998.

As the polymerization initiator to be used to prepare the crosslinkedstructure-having polymer, suitably used are water-soluble polymerizationinitiators such as potassium persulfate, sodium persulfate, ammoniumpersulfate, 2,2-azobis(2-methylpropionamidine) dihydrochloride, and4,4-azobis(4-cyanovaleric acid).

The “polymerizable group-having dispersant” is not particularly limitedso long as it has, in its molecular structure, at least a polymerizablegroup, a hydrophobic group and a hydrophilic group and, particularly,suitable examples thereof include polymerizable surfactants having, intheir molecular structures, at least a polymerizable group, ahydrophobic group and a hydrophilic group (surfactants having introducedtherein a polymerizable group), and polymer dispersant having, in theirmolecular structures, at least a polymerizable group, a hydrophobicgroup and a hydrophilic group (polymer dispersants having introducedtherein a polymerizable group).

The polymerizable group is not particularly limited so long as it is afunctional group that causes polymerization reaction in a mode of, forexample, radical polymerization, addition polymerization orpolycondensation. Examples of the radically polymerizable group include,for example, unsaturated hydrocarbon groups including vinyl, allyl,acryloyl, methacryloyl, vinylidene and vinylene groups. Examples of theaddition-polymerizable group include, for example, an isocyanate orisothiocyanate group, and other groups capable of reacting therewith,such as a hydroxyl group, an amino group, a mercapto group, and acarboxyl group. The polycondensing group is a functional group capableof polymerizing through condensation, including, for example, a carboxylgroup, a hydroxyl group, an amino group and an alkoxy group.

As the polymerizable group, preferred are radically polymerizableunsaturated hydrocarbon groups, which are preferably selected fromvinyl, allyl, acryloyl, methacryloyl, propenyl, vinylidene and vinylenegroups.

The hydrophilic group is preferably selected from carboxyl, carbonyl,hydroxyl, sulfone and sulfonic acid groups and their salts andquaternary ammonium salts.

As the polymer dispersant having introduced therein a polymerizablegroup, usable herein are those prepared by introducing a polymerizablegroup into the following synthetic polymers. Examples of the syntheticpolymers include polyvinyl alcohols; polyvinylpyrrolidones; acrylicresins and their salts such as polyacrylic acids, acrylicacid-acrylonitrile copolymers, potassium acrylate-acrylonitrilecopolymers, vinyl acetate-acrylate copolymers, acrylic acid-acrylatecopolymers; styrene-acrylic resins and their salts such asstyrene-acrylic acid copolymers, styrene-methacrylic acid copolymers,styrene-methacrylic acid-acrylate copolymers,styrene-α-methylstyrene-acrylic acid copolymers,styrene-α-methylstyrene-acrylic acid-acrylate copolymers; styrene-maleicacid copolymers, styrene-maleic anhydride copolymers,vinylnaphthalene-acrylic acid copolymers, vinylnaphthalene-maleic acidcopolymers, and their salts; and vinyl acetate copolymers and theirsalts such as vinyl acetate-ethylene copolymers, vinyl acetate-fattyacid vinylethylene copolymers, vinyl acetate-maleate copolymers, vinylacetate-crotonic acid copolymers, vinyl acetate-acrylic acid copolymers.Of those, particularly preferred are copolymers of a hydrophobicgroup-having monomer and a hydrophilic group-having monomer, andpolymers of a monomer having both a hydrophobic group and a hydrophilicgroup in its molecular structure.

In one preferred embodiment of the present invention, a polymerizablesurfactant is used as the polymerizable group-having dispersant.

The polymerizable surfactant for use in the invention preferably has ahydrophilic group selected from sulfone, sulfonic acid, carboxyl,carbonyl and hydroxyl groups and their salts and quaternary ammoniumsalts. In addition, the polymerizable group thereof is preferably anunsaturated hydrocarbon group, more specifically, a group selected fromvinyl, allyl, acryloyl, methacryloyl, propenyl vinylidene and vinylenegroups. Specific examples of such a polymerizable surfactant include theanionic allyl derivatives as described in Japanese Patent PublicationNos. 46291/1974 and 21442/1989, and Japanese Patent Laid-Open No.104802/1987; the anionic propenyl derivatives as described in JapanesePatent Laid-Open No. 221431/1987; the anionic acrylic acid derivativesas described in Japanese Patent Laid-Open Nos. 34947/1987 and11525/1980; the anionic itaconic acid derivatives as described inJapanese Patent Publication No. 34898/1971, Japanese Patent Laid-OpenNo. 30284/1976; the anionic maleic acid derivatives as described inJapanese Patent Publication No. 4157/1976, Japanese Patent Laid-Open No.30284/1976; the nonionic allyl derivatives as described in JapanesePatent Laid-Open No. 104802/1987; the nonionic propenyl derivatives asdescribed in Japanese Patent Laid-Open No. 100502/1987; the nonionicacrylic acid derivatives as described in Japanese Patent Laid-Open No.28208/1981; the nonionic itaconic acid derivatives as described inJapanese Patent Publication No. 12681/1984; the nonionic maleic acidderivatives as described in Japanese Patent Laid-Open No. 74102/1984;and the cationic allyl derivatives as described in Japanese PatentPublication No. 65824/1992.

The polymerizable surfactant is adsorbed on the surface of the coloringmaterial surface, and is excellent in dispersion stability even in thesubsequent polymerization conditions (that is, the particles can beprevented from aggregating together). Therefore, the polymerizablesurfactant is advantageous in the easiness of forming encapsulatedparticles.

In the invention, the polymerizable surfactant is preferably a compoundof formula (I) or (II) set forth below. The use of the polymerizablesurfactant of formula (I) or (II) makes it possible to form fine andstable encapsulated particles of a polymer-enveloped colorant of apigment and/or dye, and makes it possible to stably disperse thecolorant particles in aqueous media. Since the polymerizable surfactantsof formula (I) or (II) are excellent particularly in the adsorptionproperty onto the surface of the pigment and/or dye and in thedispersion stability under the subsequent polymerization conditions(that is, the particles can be prevented from aggregating together),they are advantageous in the easiness of forming encapsulated particles.Incidentally, the polymerizable surfactant of formula (I) corresponds tothose disclosed in Japanese Patent Laid-Open Nos. 320276/1993 and316909/1998.

wherein R represents a hydrogen atom, or a hydrocarbon group having from1 to 12 carbon atoms; n indicates a number falling between 2 and 20; Mrepresents an alkali metal, an ammonium salt, or an alkanolamine.

By appropriately selecting R and the value of n in formula (I), thecompound can be fitted to the degree of hydrophilicity or hydrophobicityof the coloring material surface. Preferred examples of thepolymerizable surfactant of formula (I) include compounds of formulae(III) to (VI) set forth below. These may be used singly or as a mixtureof two or more thereof.

As the polymerizable surfactant of formula (I), commercially productscan also be used. For example, SE-10N of Adekarea Soap SE Seriesmanufactured by Asahi Denka Kogyo K.K. is a polymerizable surface-activeagent of formula (I) wherein R is C₉H₁₉, n is 10 and M is NH₄, whichcorresponds to formula (III). Also, SE-20N of the same series is thesame as SE-10N, but n is 20.

The polymerizable surfactant of formula (II) is as follows:

wherein R′ represents a hydrogen atom, or a hydrocarbon group havingfrom 1 to 12 carbon atoms; n indicates a number falling between 2 and20; M represents an alkali metal, an ammonium salt, or an alkanolamine.

R′ is preferably C₉H₁₉— or C₈H₁₇—.

Except those mentioned above, other commercial products can also be usedas the polymerizable surfactant. Examples thereof include, for example,Aquaron HS Series (Aquaron HS-05, HS-10, HS-20, and HS-1025), Aquaron RNSeries (RN-10, RN-20, RN-30, RN-50, and RN-2025), New Frontier Series(New Frontier 177E, and S-510), manufactured by Daiichi Kogyo YakuhinCo., Ltd.; Adekarea Soap NE Series (NE-10, NE-20, NE-30, NE-40, andNE-50) manufacture by Asahi Denka Kogyo K.K.

The addition amount of the polymerizable surfactant preferably fallsbetween around 10 and 150% by weight, more preferably between around 20and 100% by weight, with respect to the pigment and/or dye. Bycontrolling the addition amount to at least 10% by weight, thedispersion stability of the ink composition can be improved.

By controlling the addition amount to at most 150% by weight, thegeneration of the polymerizable surfactant not adsorbed onto the pigmentand/or dye can be suppressed, and the generation of polymers besides theencapsulated particles can be prevented. As the result, this makes itpossible to obtain satisfactory ejection stability of the inkcomposition.

The colorant of a pigment enveloped in a polymer includes, for example,the encapsulated fine particles of pigments as disclosed in JapanesePatent Publication No. 94634/1995, Japanese Patent Laid-Open No.59715/1996; the pigment having a polymer group bonded to its surface asdisclosed in WO9951690; and the modified particles having bonded theretoa polymer group having a halogen group as disclosed in U.S. Pat. No.6,103,380.

Preferred embodiments of the physical properties of the polymer thatenvelops the pigment and/or dye therein are described below.

Firstly, it is preferred that the solubility parameter of the “polymerthat envelops the pigment and/or dye therein” (hereinafter designated by“SPp”) falls between 11 and 14 cal/cm³, and the difference between thesolubility parameter of the liquid component and that of the polymer(hereinafter designated by “ASP”) is at least 1.0 cal/cm³. Herein, theliquid component is an aqueous mixed liquid (aqueous medium) comprisingwater and a water-soluble organic solvent.

SPp indicates the hydrophilicity or hydrophobicity of the polymer. WhenSPp thereof is smaller than 11 cal/cm³, the hydrophobicity of thepolymer is too high and the colorant of the pigment and/or dye envelopedin the polymer has poor dispersibility in the aqueous medium. On theother hand, when SPp thereof is larger than 14 cal/cm³, the polymerswells in the aqueous medium to expand the hydrate layer and enlarge thepolymer-enveloped colorant particles, where a viscosity increase maysometime be observed, and deterioration in ejection stability and nozzleclogging readily take place. Accordingly, SPp of the polymer preferablyfalls within the range as defined above.

When ΔSP is smaller than 1.0 cal/cm³, the mixed solvent penetrates intothe polymer to dissolve and/or swell it, thereby causing a viscosityincrease, etc. As the result, the storage stability is not ensured, anddeterioration in ejection stability and nozzle clogging readily takeplace. Accordingly, the difference between the solubility parameter ofthe mixed solvent and that of the polymer preferably falls within therange as defined above.

The solubility parameter (δ) is a value obtained according to the Fedorsformula set forth below, based on the evaporation energy (Δe_(i)) of theatoms or the atomic groups constituting the chemical structure and themolar volume (Δv_(i)) thereof.δ=(ΣΔe _(i) /ΣΔv _(i))^(1/2)  <Fedors formula>(Yuji Harazaki, Basic Science of Coating (Maki Shoten, 1980), pp. 54-55)

Incidentally, the solubility parameter can also be obtained, forexample, through calculation from the heat of evaporation, calculationfrom the refractive index, calculation from the kauri-butanol value, orcalculation from the surface tension.

The acid value of the “polymer that envelops pigment and/or dye therein”preferably falls between 20 and 200 KOH mg/g, more preferably between 60and 140 KOH mg/g. In general, the acid value indicates the amount (mg)of potassium hydroxide needed for neutralizing the free fatty acidscontained in 1 g of oils and fats. In the invention, the acid value isdefined to indicate the amount (mg) of potassium hydroxide needed forneutralizing the acid group such as carboxyl group and sulfonic acidgroup contained in 1 g of the polymer.

If the acid value of the polymer is smaller than 20 KOH mg/g, thedispersion stability of the colorant in aqueous media is insufficient;but if larger than 200 KOH mg/g, aggregation readily takes place uponproduction of the colorant, and the hydrate layers of the colorantparticles expands to thereby readily cause deterioration in ejectionstability and nozzle clogging. Accordingly, the above-defined range ispreferred.

The glass transition temperature of the “polymer that envelops pigmentand/or dye therein” is preferably not higher than 25° C. When the ink ofthe invention is used in printing at room temperature on plain paper oron media exclusively for ink jet recording, the aqueous medium(comprising water and/or water-soluble organic solvent) existing aroundthe colorant particles penetrates into the plain paper or mediaexclusively for ink jet recording and therefore leaves from the vicinityof the colorant particles, thereby making the colorant particles closeto one another. In such a situation, if the glass transition temperatureof the colorant particles at the particle surface is not higher than 25°C., the polymers on the colorant particle surfaces fuse one anotherowing to the capillary pressure caused in the space between theneighboring colorant particles. Since the film formation proceeds in thestate where the coloring material (the pigment and/or dye) isencapsulated (enveloped) inside, the rubbing resistance of the image canbe particularly improved. In general, when a polymer solid, especiallyan amorphous polymer solid is heated from a low temperature up to a hightemperature, it is observed a phenomenon of an abrupt change from astate where extremely large force is required for slight deformation(glass state) to a state where significant deformation is caused evenwith small force. The temperature at which the polymer undergoes thephenomenon is referred to as a glass transition temperature. In general,the glass transition temperature is defined as follows: Using adifferential scanning calorimeter, a polymer is heated to obtain its DTAcurve, on which a tangential line is drawn from the bottom of theendothermic peak toward the endothermic change starting point, and thetemperature at which the tangential line crosses the base line isdefined as the glass transition temperature. It is known that the otherphysical properties such as elastic modulus, specific heat andrefractive index also abruptly change at the glass transitiontemperature. Therefore, also known are methods of determining the glasstransition temperature by measuring these physical properties. In theinvention, the glass transition temperature obtained with a heat-upmeasurement of differential scanning calorimeter (DSC) was employed.When the ink is used in printing on plain paper or on media exclusivelyfor ink jet recording, the glass transition temperature of the “polymerthat envelops pigment and/or dye therein” is more preferably not higherthan 15° C., even more preferably not higher than 10° C., in order thatthe colorant more favorably undergoes film formation at roomtemperature. Accordingly, the “polymer that envelops pigment and/or dyetherein” for use in the invention is preferably so designed that itsglass transition temperature is not higher than 25° C., more preferablynot higher than 15° C., still more preferably not higher than 10° C. Theglass transition temperature of the polymer can be controlled to fallwithin those ranges by appropriately selecting the kind and molecularweight of the polymer. In the case where it is possible to heat theprinted matter, depending on the glass transition temperature of the“polymer that envelops pigment and/or dye therein”, to a temperaturehigher the glass transition temperature of the polymer, the glasstransition temperature may be higher than 25° C. since the filmformation can be accomplished so long as the glass transitiontemperature is not higher than the heating temperature. However, such anembodiment causes a necessity such that the ink jet recording apparatusshould be equipped with a heating unit, and causes a problem such as anincreased cost for the apparatus. Accordingly, the glass transitiontemperature is preferably not higher than 25° C.

As so mentioned hereinabove, when the ink of the invention is used inprinting at room temperature on plain paper or on media exclusively forink jet recording, a film is formed on the surface of the printed areasand the rubbing resistance of the printed image can be particularlyimproved. In the invention, the film-forming temperature on therecording medium is preferably not higher than 25° C., more preferablynot higher than 15° C., still more preferably not higher than 10° C. Thefilm-forming temperature of the ink of the invention on a recordingmedium is determined as follows: Using an ink jet printer under apredetermined temperature environment, an ink jet recording medium of aplastic film coated with inorganic particles together with a smallamount of binder (for example, superfine-exclusive glossy film, producedby Seiko Epson Corporation) is printed with an ink sample of theinvention, at 100% duty in a region of 10 mm×10 mm of the film to form asolid print. After allowing it stands for 1 hour at a predeterminedtemperature, the printed region is rubbed with an aqueous yellowfluorescent ink pen, ZEBRA PEN2 (trademark) manufactured by Zebra K.K.,under a load of 500 g at a speed of 10 mm/sec. The temperature at whichno stain is generated is regarded as the film-forming temperature.

The colorant of a pigment and/or dye enveloped in a polymer preferablycontains a hardly water-soluble substance. As the hardly water-solublesubstance, substances generally used as film-forming promoters orfilm-making promoters are preferably used.

The solubility in water of the hardly water-soluble substance ispreferably at most 10% by weight. The presence of such a hardlywater-soluble substance having a low solubility in water, particularlyhaving a solubility in water of at most 10% by weight, in the colorantof pigment and/or dye enveloped in a polymer improves the fixingproperty of the ink jet recording ink on recording media. The reasontherefor is that the hardly water-soluble substance existing in thepolymer of the colorant according to the invention therein can lower theglass transition temperature of the polymer, therefore improving thefilm formability of the polymer.

The colorant of a pigment and/or dye enveloped in a polymer has beendescribed hereinabove. By combining the colorant with at least onecompound selected from the group consisting of acetylene glycolsurfactants, acetylene alcohol surfactants, glycol ethers and1,2-alkylene glycols, it becomes possible to accomplish stable printingwith excellent dispersion stability and ejection stability and free fromnozzle clogging for a long period of time. In addition, with a recordingmedium such as plain paper, regenerated paper or coated paper, it can beobtained a high-quality image having good drying property afterprinting, being free from bleeding, having a high printed density andexcellent color development property.

When a pigment is dispersed in water, a dispersant such as a surfactantor a polymer dispersant is generally used. However, since thesedispersants are merely adsorbed on the pigment particles, there is atendency that the dispersant is usually readily released off from thecolorant particles by some environmental factor.

As opposed to this, in the colorant of a pigment and/or dye enveloped ina polymer, particularly the colorant of a pigment and/or dye envelopedin a crosslinked structure-having polymer, for use in the invention, thepolymer firmly adheres to the colorant of the pigment and/or dye and,presumably, is hardly released off from the pigment and/or dye, toprovide a satisfactory solvent resistance. Therefore, even by thecontact with the penetrant selected from acetylene glycol surfactants,acetylene alcohol surfactants, glycol ethers and 1,2-alkylene glycols,the polymer is hardly released off from the pigment and/or dye, and ishardly swollen by the penetrant. Accordingly, the colorant for use inthe present invention has excellent dispersion stability for a longperiod of time.

On the other hand, with an ink that contains a pigment dispersion, inwhich a pigment is dispersed by the use of a dispersant such as asurfactant or a polymer dispersant, and has improved penetratingproperty, there is a tendency that the ink viscosity is increased bydispersants not adsorbed on the pigment surface originally from the timeof the dispersing step but dissolved in the liquid and by dispersantsreleased off from the pigment after the dispersing step. Therefore, thepigment content is limited in many cases. For this reason, a sufficientprinted density cannot be obtained particularly on plain paper andregenerated paper, and satisfactory color development cannot be attainedin many cases. As opposed to this, in the colorant for use in theinvention, the polymer firmly adheres to the pigment and/or dye and ishardly released off from the coloring material, and therefore it hardlycauses an increase in the ink viscosity. Thus, the ink involves anadvantage that since the viscosity of the ink can be easily lowered, alarger amount of the colorant can be contained, thereby making itpossible to obtain sufficient printed density on plain paper orregenerated paper. These reasons are referred to herein merely forexplaining the contents of the invention, which therefore should notwhatsoever restrict the scope of the invention.

Preferably, the ink jet recording ink of the invention contains apreservative, a sequestrant and a rust preventive. The preservativepreferably comprises at least one compound selected from the groupconsisting of alkylisothiazolones, chloroalkylisothiazolones,benzisothiazolones, bromonitroalcohols, oxazolidines and chloroxylenols.The sequestrant is preferably a salt of ethylenediaminetetraacetic acid.The rust preventive is preferably dicyclohexylammonium nitrate and/orbenzotriazole.

Provided that the above-mentioned preservative, sequestrant and rustpreventive are contained, the ink jet recording ink of the invention mayadditionally contain any other preservatives, sequestrants and rustpreventives.

Specific examples of the preservative are as follows. For example, asthe alkylisothiazolone, products containing octylisothiazolone as theeffective component are commercially available (for example, NS-800H,NS-800G, and NS-800P, manufactured by Nagase Kasei Kogyo K.K.). As thechloroalkylisothiazolone, products containing chloroisomethylthiazoloneas the effective component are commercially available (for example,NS-500W, NS-80D, NS-CG, NS-TM, and NS-RS, manufactured by Nagase KaseiKogyo K.K.). Products containing benzisothiazolone as the effectivecomponent are commercially available (for example, Proxel XL-2, ProxelBDN, Proxel BD20, Proxel GXL, Proxel LV, and Proxel TN, manufactured byZeneca Ltd. (England); Deniside BIT and Deniside NIPA, manufactured byNagase Kasei Kogyo K.K.). Products containing bromonitroalcohol as theeffective component are commercially available (for example, Bronopole,Miaside BT, and Miaside AS, manufactured by Nagase Kasei Kogyo K.K.).Also, a product containing chloroxylenol as the effective component iscommercially available (for example, PCMX: manufactured by Nagase KaseiKogyo K.K.). Also, products containing oxazolidine-based compound as theeffective component are commercially available (for example, NS-BP,Deniside BIT-20N, Deniside SPB, Saniset HP, Microstat 5520, Saniset SK2,Deniside NS-100, Deniside C3H, Saniset 161, Deniside CSA, Deniside CST,Deniside C3, Deniside OMP, Deniside XR-6, Deniside NM, Mordenise N769,Denisat P4, Denisat P-8, and Denisat CHR, manufactured by Nagase KaseiKogyo K.K.). Of these products, the products containing theoxazolidine-based compound as the effective component, the productscontaining chloroisomethylthiazolone as the effective component, and theproducts containing benzisothiazolone as the effective component have alarge effect.

These preservatives are preferably composite components using two ormore kinds of structures, which do not so resemble each other, than asingle component since the former can restrain resistant bacteria.

For the sequestrant, particularly preferred is a salt ofethylenediaminetetraacetic acid.

Examples of the salt of ethylenediaminetetraacetic acid include, forexample, disodium salt of ethylenediaminetetraacetic acid, trisodiumsalt of ethylenediaminetetraacetic acid, tetrasodium salt ofethylenediaminetetraacetic acid, dipotassium salt ofethylenediaminetetraacetic acid, tripotassium salt ofethylenediaminetetraacetic acid, tetrapotassium salt ofethylenediaminetetraacetic acid, diammonium salt ofethylenediaminetetraacetic acid, triammonium salt ofethylenediaminetetraacetic acid, and tetraammonium salt ofethylenediaminetetraacetic acid. In the ink jet recording ink of theinvention that contains at least the colorant of a pigment and/or dyeenveloped in a polymer, and water, preferably used are disodium salt ofethylenediaminetetraacetic acid and dipotassium salt ofethylenediaminetetraacetic acid.

The salt of ethylenediaminetetraacetic acid is effective for suppressingthe deterioration of the dispersion stability of the polymer-envelopedcolorant of a pigment and/or dye according to the invention by theinfluence of a minute amount of metal ion existing in ink cartridges orin the ink pathways in heads.

For the rust preventive, effective are dicyclohexylammonium nitrateand/or benzotriazole. These rust preventives are for preventing metalheads from being rusted, and are effective for the plated faces of headswhich are readily rusted (in particular, nozzle tip portions are readilyrusted, whereby the ejection of an ink readily becomes inferior).

Preferably, the addition amount (A) of the preservative falls between0.01% by weight and 0.1% by weight, the addition amount (B) of thesequestrant falls between 0.01% by weight and 0.5% by weight, theaddition amount (C) of the rust preventive falls between 0.01% by weightand 0.2% by weight, and A+B+C falls between 0.03% by weight and 0.8% byweight.

If the addition amount (A) of the preservative is smaller than 0.01% byweight, the ink preservation effect is small. On the other hand, iflarger than 0.1%, since the preservative gives an adverse influence onthe colorant stability in the ink and the long-term storage stability ofthe ink tends to be deteriorated, thus not being preferred.

If the amount (B) of the sequestrant in the ink of the invention issmaller than 0.01% by weight, foreign substance may be generated whenthe ink is filled in the ink cartridges in which the ink chamber is madeof an urethane foam that may contain a minute amount of metal ions. Onthe other hand, if the amount thereof is larger than 0.5% by weight, thestability of the colorant in the ink tends to be deteriorated, making ithard to store the ink for a long period of time.

If the amount (C) of the rust preventive is smaller than 0.01% byweight, the ink tends to rust the metallic part of heads, particularlythe vicinity of the nozzle tip portions when the ink jet recordingapparatus is used for a long time. On the other hand, if the amountthereof is larger than 0.2% by weight, the stability of the colorant inthe ink tends to be deteriorated, making it hard to store the ink for along period of time.

By containing such a preservative, a sequestrant and a rust preventiveas described above, the storage stability of the ink can be furtherimproved and stable ejection can be further surely attained for a longperiod of time.

For ensuring the storage stability, the clogging preventing property,the ejection stability and the long-term storage stability, the ink jetrecording ink in the present invention may further contain any othervarious additives such as wetting agent, moisturizer, dissolutionpromoter, penetration inhibitor, viscosity-controlling agent,pH-controlling agent, dissolution promoter, antioxidant, antifungalagent, corrosion inhibitor, and other sequestrants.

For suppressing the ink from drying up at the nozzle tip portions of ahead, a water-soluble organic solvent that is soluble in water and hasthe ability to retain water is preferably added as a wetting agent (ormoisturizer). Examples thereof include glycerin, ethylene glycol,diethylene glycol, triethylene glycol, polyethylene glycol having amolecular weight of at most 2000, propylene glycol, dipropylene glycol,tripropylene glycol, 1,3-propylene glycol, isopropylene glycol,isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol,1,6-hexanediol, mesoerythritol, and pentaerythritol. In the invention,particularly preferred are glycerin, ethylene glycol, diethylene glycol,and polyethylene glycol having a molecular weight of at most 2000.

In addition, examples of the component for improving the solubility ofthe ink ingredients and improving the penetrating property of the inkinto recording media such as paper, or preventing nozzles from beingclogged, include, for example, alkyl alcohols having from 1 to 4 carbonatoms such as ethanol, methanol, butanol, propanol, isopropanol, as wellas formamide, acetamide, dimethylsulfoxide, sorbitol, sorbitan, acetin,diacetin, triacetin, and sulforane. These compounds can be appropriatelyselected and used.

For controlling the penetrating property, the ink of the invention maycontain any other surfactants. The additional surfactants are preferablywell miscible with the ink of the invention, particularly those of highpenetrating property and high stability. Examples thereof include, forexample, ampholytic surfactants and nonionic surfactants. Examples ofthe ampholytic surfactants include lauryl dimethylaminoacetate betaine,2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine,cocoylamidopropyl dimethylaminoacetate betaine,polyoctylpolyaminoethylglycine and other imidazole derivatives. Examplesof the nonionic surfactants include ethers such as polyoxyethylenenonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylenedodecylphenyl ether, polyoxyethylene alkylallyl ether, polyoxyethyleneoleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether,polyoxyalkylene alkyl ether; polyoxyethyleneoleic acid; esters such aspolyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate,sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate,polyoxyethylene monooleate, polyoxyethylene stearate; as well asfluorine-containing surfactants such as fluoroalkyl esters and salts ofperfluoroalkylcarboxylic acids.

In addition, included are pH-controlling agents, amines such asdiethanolamine, triethanolamine, propanolamine, morpholine and theirmodified derivatives; inorganic hydroxides such as potassium hydroxide,sodium hydroxide, lithium hydroxide; ammonium hydroxide, quaternaryammonium salts (e.g., tetramethylammonium); carbonates such as potassiumcarbonate, sodium carbonate, lithium carbonate; and phosphates.

As still other additives, ureas such as urea, thiourea, tetramethylurea;allophanates such as allophanate, methylallophanate; biurets such asbiuret, dimethylbiuret, tetramethylbiuret; L-ascorbic acid and itssalts; and commercially-available antioxidants and UV absorbents canalso be used.

Preferably, the surface tension of the ink jet recording ink of theinvention is at most 45 mN/m, more preferably falling between 25 and 45mN/m. If the surface tension is higher than 45 mN/m, satisfactory imagesare hardly obtained, since the drying property of the printed imagebecomes poor, bleeding is readily caused, and color bleeding is caused.On the other hand, if the surface tension thereof is lower than 25 mN/m,the periphery of the nozzles of a printer tends to be subjected towetting, thereby readily causing problems in the ejection stability suchas occurrence of curving of the ejected ink droplets. The surfacetension of the ink can be measured with any ordinary surface tensionmeter.

The surface tension of the ink can be controlled to fall within theabove range, by appropriately adjusting the constituent components ofthe ink and the composition ratio thereof.

Since the colorant of the ink of the invention is a pigment or dyeenveloped in a polymer, the weather resistance including lightresistance and gas resistance of the formed images becomes satisfactory.In addition, according to the colorant of the ink of the invention, thecharacteristics of the polymer that envelops the pigment or dye can bedesigned with broadened latitude by appropriately selecting thepolymerizing monomers and other reactants. Therefore, it is possible tomake the ink have various functions (light resistance, gas resistance,coloring property, gloss, fixing property).

In ordinary ink prepared by dispersing a pigment with an ordinarydispersant (e.g., surfactant or polymer dispersant), the dispersantbasically is merely adsorbed on the pigment, and therefore it is readilyreleased from the pigment by some environmental factors. Thus released,the dispersant likely increases the ink viscosity excessively.Therefore, the colorant content is limited, and it has heretofore beenconsidered that it is difficult to obtain sufficient color developmentof images. However, in the polymer-enveloped colorant of a pigmentand/or dye in the ink of the invention, the polymer is hardly releasedoff from the pigment and/or dye. Therefore, even when the colorant isadded in a large amount, it does not increase the ink viscosity, or thatis, the viscosity of the ink of the invention can be easily lowered. Ascompared with ordinary ink in which the pigment is dispersed with anordinary dispersant, the colorant content of the ink of the inventioncan be increased, and hence it is easy to obtain images havingsufficient color development.

The constitution of the ink jet recording ink of the invention has beendescribed hereinabove. The ink jet recording ink set of the inventioncomprises a plurality of the inks. In general, it is composed of acombination of the inks of three or more different colors. For example,for the ink set, four ink compositions of magenta ink, yellow ink, cyanink and black ink may be combined; or seven ink compositions of dark andlight magenta inks, dark and light yellow inks, dark and light cyan inksand black ink may be combined. If desired, orange ink and green ink maybe further combined with those compositions.

The long-term storage stability of the ink jet recording ink and the inkjet recording ink set of the invention is excellent.

The recording method of the invention comprises ejecting ink droplets toattach a recording medium to thereby perform printing, and has a featurethat the ink jet recording ink and/or the ink jet recording ink set ofthe invention is used in the method. The recording method can besuitably carried out by mounting an ink cartridge containing ink jetrecording ink of the invention (in the case where the ink set comprisinga plurality of ink jet recording inks is to be used, an ink cartridgeseparately containing the respective ink jet recording inks) on a knownink jet recording apparatus, and performing printing with respect to arecording medium.

One preferred embodiment of the ink jet recording apparatus for useherein is so designed that an electrostrictive unit capable of vibratingbased on an electronic signal is mounted and the ink jet recording inkof the invention or the inks constituting the ink set of the inventioncan be ejected according to the vibration of the electrostrictive unit.

As the ink cartridge (storage case) for storing the ink jet recordingink, a known cartridge can be suitably used.

According to the ink jet recording ink, the ink jet recording ink setand the recording method of the present invention, it can be obtained ahigh-quality image having excellent dispersion stability and ejectionstability, being free from bleeding even on plain paper or regeneratedpaper, and having high printed density and excellent color developmentproperty. In addition, an image having sufficient rubbing resistance canbe obtained not only on plain paper and regenerated paper but also onother recording media such as coated paper.

Since the recorded matter of the invention is obtained by printingaccording to the recording method of the present invention, it has animage having sufficient rubbing resistance not only with plain paper andregenerated paper but also with other recording media such as coatedpaper.

EXAMPLES

The present invention will be illustrated in greater detail withreference to the following Examples, but the invention should not beconstrued as being limited thereto.

<Preparation of Colorant of Pigment Enveloped in Polymer (Copolymer) ofPolymerizable Group-Having Dispersant and Monomer (CopolymerizableMonomer)>

The colorants set forth below were prepared by well dispersing a pigmentin an aqueous organic solvent and/or water in the presence of apolymerizable group-having dispersant, followed by polymerizing thepolymerizable group-having dispersant alone or together with othercopolymerizable monomer in the presence of a polymerization initiator ata predetermined temperature for a predetermined period of time in areactor equipped with a stirrer, a thermometer, a temperaturecontroller, a reflux condenser and a dropping funnel. The mean particlesize of the colorant particles was measured with a Doppler-laserparticle size distribution analyzer, Microtrac UPA 150 manufactured byLeeds & Northrup. The glass transition temperature of the polymer of thecolorant was measured with a heat-scanning type calorimeter(differential scanning calorimeter: DSC) manufactured by SeikoElectronics, according to the method described above.

(Colorant 1-1: Black Colorant)

Colorant 1-1 was prepared according to the same method as in Example 1described in Japanese Patent Laid-Open No. 316909/1998. Specifically,100 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 60 parts by weight of a polymerizable surfactant of formula(IV), Adekarea Soap SE-10N (manufactured by Asahi Denka) were added to250 parts by weight of water, exposed to ultrasonic waves, and subjectedto dispersion treatment in a sand mill (manufactured by YasukawaSeisakusho) for about 2 hours. This dispersion having the carbon blackdispersed with the polymerizable surfactant was put into a reactorequipped with an ultrasonic generator, a stirrer, a temperaturecontroller, a reflux condenser and a dropping funnel. On the other hand,30 parts by weight of acrylonitrile, 9 parts by weight of styrene, 51parts by weight of n-butyl acrylate, 10 parts by weight of methacrylicacid, 10 parts by weight of the same polymerizable surfactant as above,1 part by weight of potassium persulfate and 100 parts by weight ofwater were mixed to prepare an emulsion. The emulsion was gradually anddropwise put into the above-described reactor through its droppingfunnel. After the dropwise addition, a polymerization reaction wascarried out at 60° C. for 48 hours. The resulting colorant dispersionwas neutralized with potassium hydroxide to have a pH of around 8, andfiltered through a 0.4 μm filter to remove coarse particles. Through theprocess, an intended colorant dispersion was obtained. The mean particlesize thereof was measured with a Doppler-laser particle sizedistribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 105 nm. The glass transition temperature ofcolorant 1-1 was measured with a differential scanning calorimeter(DSC), DSC 200 manufactured by Seiko Electronics, and the glasstransition temperature of the polymer of the colorant was found to be10° C.

(Colorant 1-2: Cyan Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-1, except that C.I. Pigment Blue 15:3 (copperphthalocyanine pigment, manufactured by Clariant) was used in place ofthe carbon black pigment. The mean particle size thereof was measuredwith a Doppler-laser particle size distribution analyzer, Microtrac UPA150 manufactured by Leeds & Northrup, and found to be 85 nm. The glasstransition temperature of colorant 1-2 was measured with a differentialscanning calorimeter (DSC), DSC 200 manufactured by Seiko Electronics,and the glass transition temperature of the polymer of the colorant wasfound to be 10° C.

(Colorant 1-3: Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-1, except that C.I. Pigment Red 122(dimethylquinacridone pigment, manufactured by Clariant) was used inplace of the carbon black pigment. The mean particle size thereof wasmeasured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 90nm. The glass transition temperature of colorant 1-3 was measured with adifferential scanning calorimeter (DSC), DSC 200 manufactured by SeikoElectronics, and the glass transition temperature of the polymer of thecolorant was found to be 10° C.

(Colorant 1-4: Yellow Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-1, except that C.I. Pigment Yellow 180(diketopyrrolopyrole, manufactured by Clariant) was used in place of thecarbon black pigment. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 80 nm. The glasstransition temperature of colorant 1-4 was measured with a differentialscanning calorimeter (DSC), DSC 200 manufactured by Seiko Electronics,and the glass transition temperature of the polymer of the colorant wasfound to be 10° C.

(Colorant 1-5: Black Colorant)

Colorant 1-5 was prepared according to the same method as in Example 1described in Japanese Patent Laid-Open No. 316909/1998. Specifically,100 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 60 parts by weight of a polymerizable surfactant of formula(II), Aquaron HS-10 (manufactured by Daiichi Yakuhin Kogyo) were addedto 250 parts by weight of water, exposed to ultrasonic waves, anddispersed in a sand mill (manufactured by Yasukawa Seisakusho) for about2 hours. The dispersion having carbon black dispersed with thepolymerizable surfactant was put into a reactor equipped with anultrasonic generator, a stirrer, a temperature controller, a refluxcondenser and a dropping funnel. On the other hand, 30 parts by weightof acrylonitrile, 9 parts by weight of styrene, 51 parts by weight ofn-butyl acrylate, 10 parts by weight of methacrylic acid, 10 parts byweight of the same polymerizable surfactant as above, 1 part by weightof potassium persulfate and 100 parts by weight of water were mixed toprepare an emulsion. The emulsion was gradually and dropwise put intothe reactor through its dropping funnel. After the dropwise addition, apolymerization reaction was carried out at 60° C. for 48 hours. Theresulting colorant dispersion was neutralized with potassium hydroxideto have a pH of around 8, and filtered through a 0.4 μm filter to removecoarse particles. Through the process, an intended colorant dispersionwas obtained. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 110 nm. The glasstransition temperature of the colorant was measured with a differentialscanning calorimeter (DSC), DSC 200 manufactured by Seiko Electronics,and the glass transition temperature of the polymer of the colorant wasfound to be 10° C.

(Colorant 1-6: Cyan Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-5, except that C.I. Pigment Blue 15:3 (copperphthalocyanine pigment, manufactured by Clariant) was used in place ofthe carbon black pigment. The mean particle size thereof was measuredwith a Doppler-laser particle size distribution analyzer, Microtrac UPA150 manufactured by Leeds & Northrup, and found to be 90 nm. The glasstransition temperature of the colorant was measured with a differentialscanning calorimeter (DSC), DSC 200 manufactured by Seiko Electronics,and the glass transition temperature of the polymer of the colorant wasfound to be 10° C.

(Colorant 1-7: Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-5, except that C.I. Pigment Red 122(dimethylquinacridone pigment, manufactured by Clariant) was used inplace of the carbon black pigment. The mean particle size thereof wasmeasured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 95nm. The glass transition temperature of the colorant was measured with adifferential scanning calorimeter (DSC), DSC 200 manufactured by SeikoElectronics, and the glass transition temperature of the polymer of thecolorant was found to be 10° C.

(Colorant 1-8: Yellow Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-5, except that C.I. Pigment Yellow 180(diketopyrrolopyrole, manufactured by Clariant) was used in place of thecarbon black pigment. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 85 nm. The glasstransition temperature of the colorant was measured with a differentialscanning calorimeter (DSC), DSC 200 manufactured by Seiko Electronics,and the glass transition temperature of the polymer of the colorant wasfound to be 10° C.

(Colorant 1-9: Black Colorant)

This colorant was prepared according to the same method as in Example 1described in Japanese Patent Laid-Open No. 316909/1998. Specifically, 5parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 3 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 80 parts byweight of water, and dispersed through exposure to ultrasonic waves for4 hours. 1.6 parts by weight of acrylonitrile and 0.05 parts by weightof potassium persulfate were added thereto, and a polymerizationreaction was carried out at 60° C. for 48 hours. The resultingdispersion was filtered through a 0.4 μm filter to remove coarseparticles. Through the process, an intended colorant dispersion wasobtained.

(Colorant 1-10: Black Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-9, except that a polymerizable surfactant offormula (II), Aquaron HS-10, was used in place of the polymerizablesurfactant of formula (IV), Adekarea Soap SE-10N (manufactured by AsahiDenka).

(Colorant 1-11: Cyan Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-9, except that C.I. Pigment Blue 15:3 was usedin place of the carbon black.

(Colorant 1-12: Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-9, except that C.I. Pigment Red 122 was used inplace of the carbon black.

(Colorant 1-13: Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-9, except that C.I. Pigment Red 180 was used inplace of the carbon black.

(Colorant 1-14: Black Colorant)

The intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-9, except that 2 parts by weight of dibutylfumarate was used in place of the acrylonitrile.

(Colorant 1-15: Black Colorant)

5 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 3 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 80 parts byweight of water, exposed to ultrasonic waves, and dispersed in a sandmill (manufactured by Yasukawa Seisakusho) for about 2 hours. Thedispersion having carbon black dispersed with the polymerizablesurfactant was put into a reactor equipped with an ultrasonic generator,a stirrer, a temperature controller, a reflux condenser and a droppingfunnel. 2 parts by weight of 2-hydroxyethyl acrylate and 0.05 parts byweight of potassium persulfate were added thereto, and a polymerizationreaction was carried out at 60° C. for 48 hours. The resultingdispersion was filtered through a 0.4 μm filter to remove coarseparticles. Through the process, an intended colorant dispersion wasobtained.

(Colorant 1-16: Black Colorant)

10 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 6 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 160 parts byweight of water, exposed to ultrasonic waves, and dispersed in a sandmill (manufactured by Yasukawa Seisakusho) for about 2 hours. Thedispersion having carbon black dispersed with the polymerizablesurfactant was put into a reactor equipped with an ultrasonic generator,a stirrer, a temperature controller, a reflux condenser and a droppingfunnel. On the other hand, 2 parts by weight of benzyl methacrylate, 2parts by weight of n-butyl acrylate, 1 part by weight of methacrylicacid, 0.1 parts by weight of the same polymerizable surfactant as above,0.05 parts by weight of potassium persulfate and 10 parts by weight ofwater were mixed to prepare an emulsion. The emulsion was gradually anddropwise put into the reactor through its dropping funnel. After thedropwise addition, a polymerization reaction was carried out at 60° C.for 48 hours. The resulting colorant dispersion was filtered through a0.4 μm filter to remove coarse particles. Through the process, anintended colorant dispersion was obtained.

(Colorant 1-17: Black Colorant)

10 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 6 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 160 parts byweight of water, exposed to ultrasonic waves, and dispersed in a sandmill (manufactured by Yasukawa Seisakusho) for about 2 hours. Theresulting dispersion was put into a reactor equipped with an ultrasonicgenerator, a stirrer, a temperature controller, a reflux condenser and adropping funnel. On the other hand, 1 part by weight of benzylmethacrylate, 2 parts by weight of n-butyl methacrylate, 1 part byweight of methacrylic acid, 0.1 parts by weight of the samepolymerizable surfactant as above, 0.05 parts by weight of potassiumpersulfate and 10 parts by weight of water were mixed to prepare anemulsion. The emulsion was gradually and dropwise put into the reactorthrough its dropping funnel. After the dropwise addition, apolymerization reaction was carried out at 60° C. for 48 hours. Theresulting colorant dispersion was neutralized with potassium hydroxideto have a pH of around 8, and filtered through a 0.4 μm filter to removecoarse particles. Through the process, an intended colorant dispersionwas obtained. The acid value of the colorant was 101 KOH mg/g. The acidvalue of the colorant can be considered as the acid value of thepolymer.

(Colorant 1-18: Black Colorant)

10 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 6 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 160 parts byweight of water, exposed to ultrasonic waves, and dispersed in a sandmill (manufactured by Yasukawa Seisakusho) for about 2 hours. Theresulting dispersion was put into a reactor equipped with an ultrasonicgenerator, a stirrer, a temperature controller, a reflux condenser and adropping funnel. On the other hand, 1 part by weight of benzylmethacrylate, 2 parts by weight of n-butyl methacrylate, 3 parts byweight of methacrylic acid, 0.1 parts by weight of the samepolymerizable surfactant as above, 0.05 parts by weight of potassiumpersulfate and 10 parts by weight of water were mixed to prepare anemulsion. The emulsion was gradually and dropwise put into the reactorthrough its dropping funnel. After the dropwise addition, apolymerization reaction was carried out at 60° C. for 48 hours. Theresulting colorant dispersion was neutralized with potassium hydroxideto have a pH of around 8, and filtered through a 0.4 μm filter to removecoarse particles. Through the process, an intended colorant dispersionwas obtained. The acid value of the colorant was 168 KOH mg/g. The acidvalue of the colorant can be considered as the acid value of thepolymer. The solubility parameter (6) of the polymer was 11.3. The meanparticle size thereof was measured with a Doppler-laser particle sizedistribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 110 nm. The glass transition temperature ofthe colorant was measured with a differential scanning calorimeter(DSC), DSC 200 manufactured by Seiko Electronics, and the glasstransition temperature of the polymer of the colorant was found to be17° C.

(Colorant 1-19: Black Colorant)

10 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 6 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 160 parts byweight of water, exposed to ultrasonic waves, and dispersed in a sandmill (manufactured by Yasukawa Seisakusho) for about 2 hours. Theresulting dispersion was put into a reactor equipped with an ultrasonicgenerator, a stirrer, a temperature controller, a reflux condenser and adropping funnel. On the other hand, 2 parts by weight of acrylonitrile,1 part by weight of acrylamide, 3 parts by weight of n-butylmethacrylate, 1 part by weight of methacrylic acid, 0.1 parts by weightof the same polymerizable surfactant as above, 0.05 parts by weight ofpotassium persulfate and 10 parts by weight of water were mixed toprepare an emulsion. The emulsion was gradually and dropwise put intothe reactor through its dropping funnel. After the dropwise addition, apolymerization reaction was carried out at 60° C. for 48 hours. Theresulting colorant dispersion was neutralized with potassium hydroxideto have a pH of around 8, and filtered through a 0.4 μm filter to removecoarse particles. Through the process, an intended colorant dispersionwas obtained. The acid value of the colorant was 101 KOH mg/g. The acidvalue of the colorant can be considered as the acid value of thepolymer. The solubility parameter (δ) of the polymer was 13.8. The meanparticle size thereof was measured with a Doppler-laser particle sizedistribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 105 nm. The glass transition temperature ofthe colorant was measured with a differential scanning calorimeter(DSC), DSC 200 manufactured by Seiko Electronics, and the glasstransition temperature of the polymer of the colorant was found to be13° C.

(Colorant 1-20: Black Colorant)

In the same manner as in Example 1 described in Japanese PatentLaid-Open No. 316909/1998, 5 parts by weight of a carbon black pigment,Raven C (manufactured by Columbia Carbon) and 3 parts by weight of apolymerizable surfactant of formula (IV), Adekarea Soap SE-10N(manufactured by Asahi Denka) were added to 80 parts of ion-exchangedwater in a reactor equipped with an ultrasonic generator, a stirrer, adropping unit, a water-cooling reflux condenser, a thermometer and atemperature controller, and a dispersion treatment was carried out withapplying ultrasonic waves for 4 hours. 1.6 parts by weight ofacrylonitrile and 0.05 parts by weight of potassium persulfate wereadded thereto, and a polymerization reaction was carried out at 60° C.for 48 hours. The resulting dispersion was filtered through a 0.4 μmmembrane filter to remove coarse particles.

Next, 27 parts by weight of ion-exchanged water and 0.06 parts by weightof sodium laurylsulfate were put into the reactor, to which were added100 parts by weight of ion-exchanged water and 0.5 parts by weight of apolymerization initiator, and kept at 70° C. in a nitrogen atmosphere.Then, after 3 parts by weight of Adekarea Soap SE-10N was added theretoand stirred, a mixture prepared by mixing 15 parts by weight of styrene,6 parts by weight of tetrahydrofurfuryl methacrylate, 45 parts by weightof n-butyl acrylate and 0.02 parts by weight of t-dodecylmercaptan wasdropwise put into the reactor and reacted. This was neutralized withsodium hydroxide to have a pH of 8, and filtered through 0.3 μm filterto obtain an intended colorant dispersion. The mean particle sizethereof was measured with a Doppler-laser particle size distributionanalyzer, Microtrac UPA 150 manufactured by Leeds & Northrup, and foundto be 105 nm.

(Colorant 1-21: Film-Forming Promoter-Containing Black Colorant)

Colorant 1-21 was prepared in the same manner as in Example 1 describedin Japanese Patent Laid-Open No. 316909/1998. Specifically, 100 parts byweight of carbon black (Raven C, manufactured by Columbia Carbon) and 60parts by weight of a polymerizable surfactant of formula (IV), SE-10N(manufactured by Asahi Denka) were added to 250 parts by weight ofwater, exposed to ultrasonic waves, and dispersed in a sand mill(manufactured by Yasukawa Seisakusho) for about 2 hours. The carbonblack dispersion in the polymerizable surfactant was put into a reactorequipped with an ultrasonic generator, a stirrer, a temperaturecontroller, a reflux condenser and a dropping funnel. On the other hand,30 parts by weight of acrylonitrile, 50 parts by weight of styrene, 15parts by weight of n-butyl methacrylate, 10 parts by weight ofmethacrylic acid, 10 parts by weight of the same polymerizablesurfactant as above, 15 parts by weight of ADEKA PLANON MPC-709(manufactured by Asahi Denka), 1 part by weight of potassium persulfateand 100 parts by weight of water were mixed to prepare an emulsion. Theemulsion was gradually and dropwise put into the reactor through itsdropping funnel. After the dropwise addition, a polymerization reactionwas carried out at 60° C. for 48 hours. The resulting colorantdispersion was neutralized with potassium hydroxide to have a pH ofaround 8, and filtered through a 0.4 μm filter to remove coarseparticles. Through the process, an intended colorant dispersion wasobtained. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 105 nm. The glasstransition temperature of the colorant was measured with a differentialscanning calorimeter (DSC), DSC 200 manufactured by Seiko Electronics,and the glass transition temperature of the polymer of colorant 1-21 was25° C.

(Colorant 1-22: Film-Forming Promoter-Containing Cyan Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-21, except that C.I. Pigment Blue 15:3 (copperphthalocyanine pigment, manufactured by Clariant) was used in place ofthe carbon black pigment. The mean particle size thereof was measuredwith a Doppler-laser particle size distribution analyzer, Microtrac UPA150 manufactured by Leeds & Northrup, and found to be 85 nm.

(Colorant 1-23: Film-Forming Promoter-Containing Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-21, except that C.I. Pigment Red 122(dimethylquinacridone pigment, manufactured by Clariant) was used inplace of the carbon black pigment. The mean particle size thereof wasmeasured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 90nm.

(Colorant 1-24: Film-Forming Promoter-Containing Yellow Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 1-21, except that C.I. Pigment Yellow 180(diketopyrrolopyrole, manufactured by Clariant) was used in place of thecarbon black pigment. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 80 nm.

<Preparation of Colorant of Pigment Enveloped in CrosslinkedStructure-Having Polymer>

(Colorant 2-1: Black Colorant)

Prepared was a mixture of 84 parts by weight of benzyl methacrylate, 85parts by weight of n-butyl methacrylate, 35 parts by weight of2-hydroxyethyl methacrylate, 25 parts by weight of methacrylic acid, 13parts by weight of glycidyl methacrylate and 20.0 parts by weight oft-hexylperoxy-2-ethyl hexanoate.

On the other hand, 300 parts by weight of methyl ethyl ketone was putinto a reactor, and, while sealed in nitrogen, this was heated up to 75°C. with stirring. Then, the mixture prepared in the above was dropwiseadded thereto over a period of 2 hours. After the dropwise addition,this was further reacted for 20 hours at the same temperature, and thenmethyl ethyl ketone was evaporated away to obtain polymer (A). ThroughGPC, polymer (A) was found to have a weight-average molecular weight ofabout 13000. The acid value of polymer (A) was 76 KOH mg/g.

6 parts by weight of polymer (A) prepared in the process of producingcolorant 2-1 was dissolved in 50 parts by weight of toluene addedthereto. Then, 20 parts by weight of carbon black, Raven C (manufacturedby Columbia Carbon) was added thereto, and dispersed in a bead milldisperser, and the beads used were removed through filtration. To theresulting filtrate, added was 0.3 parts by weight ofparamenthanediamine, and dissolved by stirring with a stirrer.

Next, while stirred and exposed to ultrasonic waves, the organic solventphase was emulsified with 60 parts by weight of ion-exchanged waterdropwise added thereto. Toluene was completely removed from theresulting emulsion at 60° C. under reduced pressure, and a crosslinkingreaction was carried out at 80° C. for 5 hours. Next, the pH thereof.was controlled to around 8 with potassium hydroxide, and this wasfiltered through a 0.4 μm filter to obtain an intended colorantdispersion. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 180 nm. The solidcontent thereof was 30.5%.

(Colorant 2-2: Black Colorant)

30 parts by weight of polymer (A) prepared in the process of producingcolorant 2-1 was dissolved in 100 parts by weight of toluene addedthereto. Then, 20 parts by weight of carbon black, Raven C (manufacturedby Columbia Carbon) was added thereto, and dispersed in a bead milldisperser, and the beads used were removed through filtration. To theresulting filtrate, added was 1.5 parts by weight ofparamenthanediamine, and dissolved by stirring with a stirrer.

Next, while stirred and exposed to ultrasonic waves, the organic solventphase was emulsified with 100 parts by weight of ion-exchanged waterdropwise added thereto. Toluene was completely removed from theresulting emulsion at 60° C. under reduced pressure, and a crosslinkingreaction was carried out at 80° C. for 5 hours. Next, the pH thereof wascontrolled to around 8 with potassium hydroxide, and this was filteredthrough a 0.4 μm filter to obtain an intended colorant dispersion. Themean particle size thereof was measured with a Doppler-laser particlesize distribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 180 nm. The solid content thereof was 34%.

A part of the dispersion was centrifuged to separate the colorant fromthe liquid phase, and the liquid phase was analyzed through GPC, whichconfirmed that the amount of the water-soluble substance derived fromthe polymer was 600 ppm.

(Colorant 2-3: Cyan Colorant)

Prepared was a mixture of 84 parts by weight of benzyl methacrylate, 85parts by weight of n-butyl acrylate, 35 parts by weight of2-hydroxyethyl methacrylate, 25 parts by weight of methacrylic acid and20.0 parts by weight of t-hexylperoxy-2-ethyl hexanoate.

On the other hand, 300 parts by weight of methyl ethyl ketone was putinto a reactor, and, while sealed in nitrogen, this was heated up to 75°C. with stirring. Then, the mixture prepared in the above was dropwiseadded thereto over a period of 2 hours. After the dropwise addition,this was further reacted for 20 hours at the same temperature to obtaina solution of a polymer having a weight-average molecular weight of13000. To the polymer solution, added were 5 parts by weight of2-methacryloyloxyethyl isocyanate (Karenzu MOI manufactured by ShowaDenko), 0.1 parts by weight of dibutyltin laurate and 200 ppm ofhydroquinone, and again reacted under heat at 70° C. for 5 hours toobtain polymer (B) having an unsaturated hydrocarbon group as acrosslinking reactive group.

30 parts by weight of polymer (B) was dissolved in 50 parts by weight oftoluene added thereto, to which was added 20 parts by weight of C.I.Pigment Blue 15:3. The mixture was subjected to dispersion treatmentwith a bead mill disperser, then the beads used were removed throughfiltration, and the resulting filtrate was mixed with 0.3 parts byweight of diethylene glycol dimethacrylate added thereto in a mixer, anddissolved therein.

Next, while stirred and exposed to ultrasonic waves, the organic solventphase was emulsified with 60 parts by weight of ion-exchanged waterdropwise added thereto. The ion-exchanged water contained 1% by weightof a polymerization initiator, potassium persulfate, dissolved therein.The emulsion was subjected to crosslinking reaction at 75° C. for 10hours, and toluene was completely removed therefrom at 60° C. underreduced pressure. The pH of the emulsion was controlled to around 8 withpotassium hydroxide, and this was filtered through a 0.4 μm filter toobtain an intended colorant dispersion. The mean particle size thereofwas measured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 180nm. The solid content thereof was 30.5%.

(Colorant 2-4: Magenta Colorant)

30 parts by weight of polymer (B) prepared in the process of producingcolorant 2-3 was dissolved in 50 parts by weight of toluene addedthereto. Then, 20 parts by weight of C.I. Pigment Red 122 and 2 parts byweight of a reactive (or polymerizable) surfactant, Adekarea Soap NE-10manufactured by Asahi Denka, were added thereto, and the mixture wassubjected to dispersion treatment in a bead mill disperser, and thebeads used were removed through filtration. To the resulting filtrate,added was 2 parts by weight of diethylene glycol dimethacrylate, anddissolved by stirring with a stirrer.

Next, while stirred and exposed to ultrasonic waves, the organic solventphase was emulsified with 60 parts by weight of ion-exchanged waterdropwise added thereto. The ion-exchanged water contained 1% by weightof a polymerization initiator, potassium persulfate, dissolved therein.The emulsion was subjected to crosslinking reaction at 75° C. for 10hours, and toluene was completely removed therefrom at 60° C. underreduced pressure. The pH of the emulsion was controlled to around 8 withpotassium hydroxide, and this was filtered through a 0.4 μm filter toobtain an intended colorant dispersion. The mean particle size thereofwas measured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 150nm. The solid content thereof was 30%.

(Colorant 2-5: Black Colorant)

Prepared was a mixture of 85 parts by weight of benzyl methacrylate, 85parts by weight of n-butyl acrylate, 40 parts by weight of2-hydroxyethyl methacrylate, 55 parts by weight of methacrylic acid, 15parts by weight of glycidyl methacrylate and 20.0 parts by weight oft-hexylperoxy-2-ethyl hexanoate.

On the other hand, 300 parts by weight of methyl ethyl ketone was putinto a reactor, and, while sealed in nitrogen, this was heated up to 75°C. with stirring. Then, the mixture prepared in the above was dropwiseadded thereto over a period of 2 hours. After the dropwise addition,this was further reacted for 20 hours at the same temperature, and thenmethyl ethyl ketone was evaporated away to obtain a polymer. ThroughGPC, the polymer was found to have a weight-average molecular weight ofabout 13000. The acid value of the polymer was 145 KOH mg/g.

6 parts by weight of the polymer was dissolved in 50 parts by weight oftoluene added thereto. Then, 20 parts by weight of carbon black, Raven C(manufactured by Columbia Carbon), was added thereto, and the mixturewas subjected to dispersion treatment in a bead mill disperser, and thebeads used were removed through filtration. To the resulting filtrate,added was 0.3 parts by weight of paramenthanediamine, and dissolved bystirring with a stirrer.

Next, while stirred and exposed to ultrasonic waves, the organic solventphase was emulsified with 60 parts by weight of ion-exchanged waterdropwise added thereto. Toluene was completely removed from theresulting emulsion at 60° C. under reduced pressure, and a crosslinkingreaction was carried out at 80° C. for 5 hours. Next, the pH thereof wascontrolled to around 8 with potassium hydroxide, and this was filteredthrough a 0.4 μm filter to obtain an intended colorant dispersion. Thesolubility parameter (δ) of the polymer was 11.0. The mean particle sizewas measured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 180nm. The glass transition temperature of the colorant was measured with adifferential scanning colorimeter (DSC), DSC 200 manufactured by SeikoElectronics, and the glass transition temperature of the polymer of thecolorant was found to be 21° C.

The colorant of a pigment enveloped in a crosslinked structure-havingpolymer can be obtained also by a different method that comprises welldispersing a pigment in an aqueous organic solvent and/or water togetherwith a polymerizable group-having dispersant, and carrying out apolymerization reaction of the polymerizable group-having dispersantwith a crosslinking monomer in the presence of a polymerizationinitiator in a reactor equipped with a stirrer, a thermometer, atemperature controller, a reflux condenser and a dropping funnel, at apredetermined temperature for a predetermined period of time. Examplesof colorants produced according to the method are set forth below.

(Colorant 2-6: Black Colorant)

Colorant 2-6 was prepared according to the same method as in Example 1described in Japanese Patent Laid-Open No. 316909/1998. Specifically, 50parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 30 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 200 parts byweight of water, exposed to ultrasonic waves, and subjected todispersing treatment in a sand mill (manufactured by YasukawaSeisakusho) for about 2 hours. The dispersion having carbon blackdispersed in the polymerizable surfactant was put into a reactorequipped with an ultrasonic generator, a stirrer, a temperaturecontroller, a reflux condenser and a dropping funnel. On the other hand,16 parts by weight of acrylonitrile, 2.4 parts by weight ofdivinylbenzene, 1 part by weight of potassium persulfate and 100 partsby weight of water were mixed to prepare an emulsion. The emulsion wasgradually and dropwise put into the reactor through its dropping funnel.After the dropwise addition, a polymerization reaction was carried outat 60° C. for 48 hours. The resulting colorant dispersion was controlledto have a pH of around 8 with potassium hydroxide, and then filteredthrough a 0.4 μm filter to remove coarse particles. Through the process,an intended colorant dispersion was obtained. The mean particle sizethereof was measured with a Doppler-laser particle size distributionanalyzer, Microtrac UPA 150 manufactured by Leeds & Northrup, and foundto be 110 nm. The glass transition temperature of the colorant wasmeasured with a differential scanning calorimeter (DSC), DSC 200manufactured by Seiko Electronics, and the glass transition temperatureof the polymer of the colorant was found to be 20° C.

(Colorant 2-7: Black Colorant)

An intended colorant dispersion was obtained in the same manner asabove, except that a polymerizable surfactant of formula (II), AquaronHS-10 was used in place of the polymerizable surfactant of formula (IV),Adekarea Soap SE-10 (manufactured by Asahi Denka) used in preparingcolorant 2-6.

(Colorant 2-8: Magenta Colorant)

Colorant 2-8 was prepared according to the same method as in Example 1described in Japanese Patent Laid-Open No. 316909/1998. Specifically, 50parts by weight of C.I. Pigment Red 122 and 30 parts by weight of apolymerizable surfactant of formula (IV), SE-10N (manufactured by AsahiDenka) were added to 200 parts by weight of water, exposed to ultrasonicwaves, and subjected to dispersion treatment in a sand mill(manufactured by Yasukawa Seisakusho) for about 2 hours. The dispersionhaving C.I. Pigment Red 122 dispersed with the polymerizable surfactantwas put into a reactor equipped with an ultrasonic generator, a stirrer,a temperature controller, a reflux condenser and a dropping funnel. Onthe other hand, 16 parts by weight of acrylonitrile, 5 parts by weightof diallyl isophthalate, 1 part by weight of potassium persulfate and100 parts by weight of water were mixed to prepare an emulsion. Theemulsion was gradually and dropwise put into the reactor through itsdropping funnel. After the dropwise addition, a polymerization reactionwas carried out at 60° C. for 48 hours. The resulting colorantdispersion was controlled to have a pH of around 8 with potassiumhydroxide, and then filtered through a 0.4 μm filter to remove coarseparticles. Through the process, an intended colorant dispersion wasobtained. The mean particle size thereof was measured with aDoppler-laser particle size distribution analyzer, Microtrac UPA 150manufactured by Leeds & Northrup, and found to be 115 nm.

(Colorant 2-9: Cyan Colorant)

50 parts by weight of C.I. Pigment Blue 15:3 and 30 parts by weight of apolymerizable surfactant of formula (IV), SE-10N (manufactured by AsahiDenka) were added to 300 parts by weight of water in a reactor equippedwith an ultrasonic generator, a stirrer, a temperature controller, areflux condenser and a dropping funnel, and ultrasonically dispersed for4 hours. Next, 16 parts by weight of2-acrylamido-2-methylpropanesulfonic acid, 3 parts by weight ofacrylonitrile, 5 parts by weight of divinylbenzene and 0.5 parts byweight of potassium persulfate were added thereto, and a polymerizationreaction was carried out at 60° C. for 48 hours. The pH thereof wascontrolled to around 8 with potassium hydroxide, and this was filteredthrough a 0.4 μm filter to remove coarse particles. The process gave anintended colorant dispersion.

(Colorant 2-10: Black Colorant)

50 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 30 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 800 parts byweight of water in a reactor equipped with an ultrasonic generator, astirrer, a temperature controller, a reflux condenser and a droppingfunnel, and ultrasonically dispersed for 4 hours. Next, 16 parts byweight of acrylonitrile, 2.4 parts by weight of divinylbenzene, 5 partsby weight of fumaric acid and 0.5 parts by weight of potassiumpersulfate were added thereto, and a polymerization reaction was carriedout at 60° C. for 48 hours. The pH thereof was controlled to around 8with potassium hydroxide, and this was filtered through a 0.4 μm filterto remove coarse particles. The process gave an intended colorantdispersion. The acid value of the colorant was 126 KOH mg/g.

(Colorant 2-11: Black Colorant)

50 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 30 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 800 parts byweight of water in a reactor equipped with an ultrasonic generator, astirrer, a temperature controller, a reflux condenser and a droppingfunnel, and ultrasonically dispersed for 4 hours. Next, 16 parts byweight of acrylonitrile, 2.4 parts by weight of divinylbenzene and 0.5parts by weight of potassium persulfate were added thereto, and apolymerization reaction was carried out at 60° C. for 48 hours. The pHthereof was controlled to around 8 with potassium hydroxide, and thiswas filtered through a 0.4 μm filter to remove coarse particles. Theprocess gave an intended colorant dispersion. The acid value of thecolorant was 45 KOH mg/g. The solubility parameter (δ) of the polymerwas 13.7.

(Colorant 2-12: Black Colorant)

50 parts by weight of carbon black (Raven C, manufactured by ColumbiaCarbon) and 30 parts by weight of a polymerizable surfactant of formula(IV), SE-10N (manufactured by Asahi Denka) were added to 800 parts byweight of water in a reactor equipped with an ultrasonic generator, astirrer, a temperature controller, a reflux condenser and a droppingfunnel, and ultrasonically dispersed for 4 hours. Next, 16 parts byweight of acrylonitrile, 2.4 parts by weight of divinylbenzene, 3 partsby weight of fumaric acid and 0.5 parts by weight of potassiumpersulfate were added thereto, and a polymerization reaction was carriedout at 60° C. for 48 hours. The pH thereof was controlled to around 8with potassium hydroxide, and this was filtered through a 0.4 μm filterto remove coarse particles. The process gave an intended colorantdispersion. The acid value of the colorant was 95 KOH mg/g. Thesolubility parameter (δ) of the polymer was 13.9.

(Colorant 2-13: Magenta Colorant)

10 parts by weight of C.I. Pigment Red 122 and 6 parts by weight of apolymerizable surfactant of formula (IV), SE-10N (manufactured by AsahiDenka) were added to 160 parts by weight of water, exposed to ultrasonicwaves, and dispersed in a sand mill (manufactured by YasukawaSeisakusho) for about 2 hours. The dispersion was put into a reactorequipped with an ultrasonic generator, a stirrer, a temperaturecontroller, a reflux condenser and a dropping funnel. On the other hand,1 part by weight of benzyl methacrylate, 2 parts by weight of n-butylmethacrylate, 0.2 parts by weight of dicyclopentanyl dimethacrylate, 1part by weight of methacrylic acid, 0.1 parts by weight of the samepolymerizable surfactant as above, 0.05 parts by weight of potassiumpersulfate and 10 parts by weight of water were mixed to prepare anemulsion. This was gradually and dropwise put into the reactor throughits dropping funnel. After the dropwise addition, a polymerizationreaction was carried out at 60° C. for 48 hours. The resulting colorantdispersion was controlled to have a pH of around 8 with potassiumhydroxide, and then filtered through a 0.4 μm filter to remove coarseparticles. The process gave an intended colorant dispersion. The acidvalue thereof was 100 KOH mg/g.

(Colorant 2-14: Magenta Colorant)

10 parts by weight of C.I. Pigment Red 122 and 6 parts by weight of apolymerizable surfactant of formula (IV), SE-10N (manufactured by AsahiDenka) were added to 160 parts by weight of water, exposed to ultrasonicwaves, and dispersed in a sand mill (manufactured by YasukawaSeisakusho) for about 2 hours. The dispersion was put into a reactorequipped with an ultrasonic generator, a stirrer, a temperaturecontroller, a reflux condenser and a dropping funnel. On the other hand,1 part by weight of benzyl methacrylate, 2 parts by weight of n-butylmethacrylate, 0.2 parts by weight of 1,6-hexanediol dimethacrylate, 2parts by weight of methacrylic acid, 0.1 parts by weight of the samepolymerizable surfactant as above, 0.05 parts by weight of potassiumpersulfate and 10 parts by weight of water were mixed to prepare anemulsion. This was gradually and dropwise put into the reactor throughits dropping funnel. After the dropwise addition, a polymerizationreaction was carried out at 60° C. for 48 hours. The resulting colorantdispersion was controlled to have a pH of around 8 with potassiumhydroxide, and then filtered through a 0.4 μm filter to remove coarseparticles. The process gave an intended colorant dispersion. The acidvalue thereof was 165 KOH mg/g. The solubility parameter (δ) of thepolymer was 11.0.

(Colorant 2-15: Cyan Colorant)

50 parts by weight of C.I. Pigment Blue 15:3 and 30 parts by weight of apolymerizable surfactant of formula (IV), SE-10N (manufactured by AsahiDenka) were added to 800 parts by weight of water in a reactor equippedwith an ultrasonic generator, a stirrer, a temperature controller, areflux condenser and a dropping funnel, and ultrasonically dispersed for4 hours. Next, 16 parts by weight of2-acrylamido-2-methylpropanesulfonic acid, 3 parts by weight ofacrylonitrile, 5 parts by weight of divinylbenzene and 0.5 parts byweight of potassium persulfate were added thereto, and a polymerizationreaction was carried out at 60° C. for 48 hours. The colorant dispersionwas controlled to have a pH of around 8 with potassium hydroxide, andthis was filtered through a 0.4 μm filter to remove coarse particles.The process gave an intended colorant dispersion. The acid value of thecolorant was 98 KOH mg/g.

(Colorant 2-16: Cyan Colorant)

50 parts by weight of C.I. Pigment Blue 15:3 and 20 parts by weight of apolymerizable surfactant of formula (IV), SE-10N (manufactured by AsahiDenka) were added to 800 parts by weight of water in a reactor equippedwith an ultrasonic generator, a stirrer, a temperature controller, areflux condenser and a dropping funnel, and ultrasonically dispersed for4 hours. Next, 12 parts by weight of acrylonitrile, 30 parts by weightof 2-acrylamido-2-methylpropanesulfonic acid, 45 parts by weight ofbenzyl methacrylate, 45 parts by weight of n-butyl methacrylate and 0.5parts by weight of potassium persulfate were added thereto, and apolymerization reaction was carried out at 60° C. for 48 hours. Thecolorant dispersion was controlled to have a pH of around 8 withpotassium hydroxide, and this was filtered through a 0.4 μm filter toremove coarse particles. The process gave an intended colorantdispersion. The acid value of the colorant was 137 KOH mg/g. Thesolubility parameter (δ) of the polymer was 11.1

<Preparation of Colorant of Dye Enveloped in Polymer (Copolymer) ofPolymerizable Group-Having Dispersant and Monomer (CopolymerizableMonomer)>

Examples of colorants using a disperse dye as the dye are set forthbelow. Water-insoluble dyes can be preferably used. Also, oil-solubledyes, vat dyes, sulfide dyes, organic solvent-soluble dyes, and reactivedyes can be used.

(Colorant 3-1: Black Colorant)

100 parts by weight of ion-exchanged water was put into a reactorequipped with an ultrasonic generator, a stirrer, a temperaturecontroller, a reflux condenser and a dropping funnel. While it wasstirred at 70° C. in a nitrogen atmosphere, 0.2 parts by weight of apolymerization initiator, potassium persulfate, was added thereto, andkept at the temperature. In a different vessel, 25 parts by weight ofstyrene, 20 parts by weight of benzyl methacrylate, 35 parts by weightof n-butyl acrylate and 5 parts by weight of methacrylic acid were mixedand dissolved to prepare a monomer solution. 130 parts by weight of adisperse dye, Disperse Black 1, was added to the monomer solution anddissolved therein. To this were added 300 parts by weight ofion-exchanged water and 3 parts by weight of a polymerizable surfactant(polymerizable group-having dispersant), Adekarea Soap SE-10N(manufactured by Asahi Denka), and ultrasonically stirred for 30 minutesto prepare an emulsion. The emulsion was dropwise added to the reactor,and after the dropwise addition, a polymerization reaction was carriedout at the above-describe temperature for 8 hours. The colorantdispersion thus obtained was neutralized to have a pH of around 8 withpotassium hydroxide, and then filtered through a 0.4 μm filter to removecoarse particles. The process gave an intended colorant dispersion. Themean particle size thereof was measured with a Doppler-laser particlesize distribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 120 nm. The glass transition temperature ofthe colorant was measured with a differential scanning calorimeter(DSC), DSC 200 manufactured by Seiko Electronics, and the glasstransition temperature of the polymer of the colorant was found to be13° C.

(Colorant 3-2: Cyan Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 3-1, except that Disperse Blue 3 was used inplace of Disperse Black 1. The glass transition temperature of thepolymer of colorant 3-2 was 13° C.

(Colorant 3-3: Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 3-1, except that Disperse Red 60 was used inplace of Disperse Black 1. The glass transition temperature of thepolymer of colorant 3-3 was 13° C.

(Colorant 3-4: Yellow Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 3-1, except that Disperse Yellow 3 was used inplace of Disperse Black 1. The glass transition temperature of thepolymer of colorant 3-4 was 13° C.

(Colorant 3-5: Film-Forming Promoter-Containing Black Colorant)

100 parts by weight of ion-exchanged water was put into a reactorequipped with a dropping unit, a thermometer, a water-cooling refluxcondenser and a stirrer. While it was stirred at 70° C. in a nitrogenatmosphere, 0.2 parts by weight of a polymerization initiator, potassiumpersulfate was added thereto, and kept at the temperature. On the otherhand, 130 parts by weight of a disperse dye 1 was dissolved in a monomersolution comprising 15 parts by weight of styrene, 2 parts by weight ofglycidyl methacrylate, 16 parts by weight of benzyl methacrylate, 50parts by weight of n-butyl methacrylate, 15 parts by weight of afilm-forming promoter, ADEKA PLANON MPC-709 (manufactured by AsahiDenka) and 0.02 parts by weight of t-dodecylmercaptan, and this wasadded to 80 parts by weight of ion-exchanged water having added thereto0.05 parts by weight of sodium laurylsulfate, to prepare an emulsion.The emulsion was dropwise added to the reactor kept at 70° C., throughits dropping funnel. After the dropwise addition, the pH thereof wascontrolled to around 8 with potassium hydroxide. This was filteredthrough a 0.4 μm filter to remove coarse particles to obtain an intendedcolorant dispersion. The glass transition temperature of the colorantwas measured with a differential scanning calorimeter (DSC), DSC 200manufactured by Seiko Electronics, and found to be 25° C.

(Colorant 3-6: Cyan Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 3-5, except that Disperse Blue 3 was used inplace of Disperse Black 1.

(Colorant 3-7: Magenta Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 3-5, except that Disperse Red 60 was used inplace of Disperse Black 1.

(Colorant 3-8: Yellow Colorant)

An intended colorant dispersion was obtained in the same manner as thatfor preparing colorant 3-5, except that Disperse Yellow 3 was used inplace of Disperse Black 1.

<Preparation of Colorant of Pigment Enveloped in Polymer>

(Colorant 4-1: Black Pigment Prepared Through Phase ConversionEmulsification)

A colorant of a pigment enveloped in a polymer was prepared in the samemanner as that described in Japanese Patent Laid-Open No. 191972/2000.Specifically, 20 parts by weight of a polymerization catalyst, methylethyl ketone, 15 parts by weight of styrene, 12 parts by weight ofn-butyl acrylate, 3 parts by weight of 2-hydroxyethyl methacrylate, 6parts by weight of silicone macromer FM-0711 manufactured by Chisso, 5parts by weight of styrene-acrylonitrile macromer AN-6 manufactured byTo a Gosei, 5 parts by weight of dimethylaminoethyl methacrylate, and0.6 parts by weight of a polymer chain transfer agent,n-dodecylmercaptan were fed into a reactor equipped with a stirrer, atemperature controller, a reflux condenser and a dropping funnel, andwell purged with nitrogen. On the other hand, 15 parts by weight ofstyrene, 12 parts by weight of n-butyl acrylate, 3 parts by weight of2-hydroxyethyl methacrylate, 6 parts by weight of silicone macromerFM-0711 manufactured by Chisso, 5 parts by weight ofstyrene-acrylonitrile macromer AN-6 manufactured by Toa Gosei, 5 partsby weight of dimethylaminoethyl methacrylate, 2.4 parts by weight of apolymer chain transfer agent, n-dodecylmercaptan in 60 parts by weightof methyl ethyl ketone, and 0.1 parts by weight of a polymerizationinitiator, 2,2′-azobis(2,4-dimethylvaleronitrile) were dissolved in 5parts by weight of methyl ethyl ketone in a separate vessel. This wasput into the reactor, reacted at 65° C. for 2 hours, and then aged at70° C. for 2 hours to obtain a methyl ethyl ketone solution of acopolymer. The number-average molecular weight of the copolymer wasabout 10,000 (measured through gel permeation chromatography). Thecopolymer solution was dried under reduced pressure to isolate thecopolymer. 20 parts by weight of the copolymer was dissolved in 100parts by weight of methyl ethyl ketone, to which was added aqueous 30%gluconic acid to partially neutralize the salt-forming group of thecopolymer. 400 parts by weight of ion-exchanged water and 80 parts byweight of carbon black were added thereto, and kneaded in a bead mill.From the mixture, the organic solvent was completely removed at 60° C.under reduced pressure. This was filtered through a 0.4 μm filter toremove coarse particles to obtain an intended colorant dispersion. Themean particle size thereof was measured with a Doppler-laser particlesize distribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 120 nm. The glass transition temperature ofthe colorant was measured with a differential scanning calorimeter(DSC), DSC 200 manufactured by Seiko Electronics, and the glasstransition temperature of the polymer of the colorant was 8° C.

(Colorant 4-2: Black Pigment Prepared Through Phase ConversionEmulsification)

A colorant of a pigment enveloped in a polymer was prepared in the samemanner as that described in Japanese Patent Laid-Open No. 43636/1999.Specifically, 300 parts by weight of methyl ethyl ketone was fed into aflask reactor equipped with a stirrer, a temperature controller, areflux condenser and a dropping funnel, and heated up to 75° C. withstirring in a nitrogen atmosphere. On the other hand, 50 parts by weightof styrene, 150 parts by weight of n-butyl methacrylate, 70 parts byweight of butyl acrylate, 35 parts by weight of 2-hydroxyethylmethacrylate, 25 parts by weight of methacrylic acid, and 6.5 parts byweight of a polymerization initiator, Perbutyl O (tert-butylperoxyoctoate by Nippon Yushi) were mixed in a separate vessel, and theresulting mixture was fed into the dropping funnel of the reactor anddropwise added to the reactor over a period of 2 hours. After thedropwise addition, this was reacted for 15 hours at the temperature toobtain a methyl ethyl ketone solution of a carboxyl group-having vinylcopolymer. The acid value of the solid component of the copolymersolution was 70 KOH mg/g; and the number-average molecular weight of thecopolymer was about 12500 (measured through gel permeationchromatography). Next, 15 parts by weight of C.I. Pigment Blue 15:3, 15parts by weight of the carboxyl group-having vinyl copolymer solution inmethyl ethyl ketone, 0.8 parts by weight of dimethylethanolamine, and44.2 parts by weight of ion-exchanged water were mixed with stirring toprepare a primary mixture, and this was put into a bead mill to disperseit. The dispersion was diluted two-fold with water added thereto. Whilethis was stirred with a stirrer, 1 N HCl was added thereto to make ithave pH of from 3 to 5. Through the process, the carboxyl group-havingvinyl copolymer in the dispersion was insolubilized and fixed to theC.I. Pigment Blue 15:3. The process thus gave a dispersion of C.I.Pigment Blue 15:3 enveloped in a carboxyl group-having vinyl copolymer.This was filtered under suction, and the residue was washed with waterto obtain a wet cake of C.I. Pigment Blue 15:3 enveloped in the carboxylgroup-having vinyl copolymer. While the wet cake was stirred with astirrer, aqueous 10% sodium hydroxide solution was added thereto to makeit have pH of from 8.5 to 9.5. This was further stirred for 1 hour, andwater was added thereto to make it have a nonvolatile content of 25%.Filtered through a 0.4 μm filter to remove coarse particles, this gavean intended colorant dispersion. The mean particle size thereof wasmeasured with a Doppler-laser particle size distribution analyzer,Microtrac UPA 150 manufactured by Leeds & Northrup, and found to be 100nm. The glass transition temperature of the colorant was measured with adifferential scanning calorimeter (DSC), DSC 200 manufactured by SeikoElectronics, and the glass transition temperature of the polymer of thecolorant was 16° C.

<Preparation of Colorant of Oil-Soluble Dye Enveloped in CrosslinkedStructure-Having Polymer>

(Colorant 5-1: Cyan Colorant)

30 parts by weight of polymer (A) prepared for colorant 2-1 wasdissolved in 100 parts by weight of toluene added thereto, and 20 partsby weight of an oil-soluble dye, Vail Fast Blue 2606 (by OrientChemical) was added thereto and dispersed with a bead mill disperser.The beads used were removed through filtration, and 1.5 parts by weightof paramenthanediamine was added to the filtrate and dissolved bystirring with a stirrer.

Next, while stirred and exposed to ultrasonic waves, the organic solventphase was emulsified with 100 parts by weight of ion-exchanged waterdropwise added thereto. Toluene was completely removed from theresulting emulsion at 60° C. under reduced pressure, and a crosslinkingreaction was carried out at 80° C. for 5 hours. Next, the pH thereof wascontrolled to around 8 with potassium hydroxide, and this was filteredthrough a 0.4 μm filter to obtain an intended colorant dispersion. Themean particle size thereof was measured with a Doppler-laser particlesize distribution analyzer, Microtrac UPA 150 manufactured by Leeds &Northrup, and found to be 180 nm. The solid content was 34%.

<Preparation of Pigment Having Polymer Group Bonded to Its Surface>

(Colorant 6-1: Black Pigment)

An intended pigment having a polymer group bonded to its surface wasprepared according to the method described in Example III and Example IVin WO995169 and Japanese Patent Laid-Open No. 95987/2000. The detailsthereof are described below.

11.4 g of sodium nitrite, 28.0 g of sulfanilic acid and 1200 g of 0° C.water were fed into a reactor to form diazonium sulfanilate, to whichwas added 200 g of a carbon black pigment, Raven C. When the generationof nitrogen ceased, the reaction mixture was concentrated, and furtherreacted at an elevated temperature. The resulting mixture was extractedwith ethanol for 12 hours in a Soxhlet's extractor to remove unreactedcompounds and side products, and this was again dissolved in water andfiltered to obtain a dispersion of about 20 wt. % sulfanilate-processedcarbon black pigment. On the other hand, 3.6 g of aminostyrene, 2.1 g ofsodium nitrite and 150 g of water were fed into a separate reactor toform a diazonium salt of 4-aminostyrene, and this was dissolved in 10 gof ethanol. The sulfanilate-processed carbon black pigment dispersionwas added to the diazonium salt solution and reacted for 18 hours withstirring. Then, this was filtered and purified through Soxhletextraction to obtain a dispersion of a carbon black pigment having4-aminostyrene added to its surface. Next, 30 g of deionized water wasdegassed in a nitrogen atmosphere at 90° C. in a reactor, and a mixtureof 28.13 g of the 4-aminostyrene-added carbon black pigment dispersion,2.0 g of methyl methacrylate, 2.0 g of butyl acrylate, and 1.0 g ofpolyethylene glycol 2000 monomethyl ether acrylate dissolved in 3.0 g ofdeionized water was dropwise added thereto over a period of 20 minutes.0.22 g of potassium persulfate was added thereto and reacted at 80° C.for 18 hours. The resulting product was concentrated under reducedpressure, and extracted with acetone in an Soxhlet's extractor to removethe non-added polymer. The process gave an intended dispersion of apigment having a polymer group bonded to its surface.

<Preparation of Inks>

Inks having the composition set forth below (see Table 1 to Table 32)were produced according to the following process. An aqueous mediumprepared beforehand was gradually and dropwise added to theabove-obtained dispersion of the colorant with stirring. After thedropwise addition, this was fully stirred, and filtered through a 5 μmmembrane filter to obtain an ink.

In Table 1 below, “Ex. 1” indicates the ink of Example 1; and “Comp. 1”indicates the ink of Comparative Example 1. The same shall apply to theother example numbers in Table 1 and also to the example numbers in theother Tables.

In Tables 1 to 32 below, the numerals relating to the compositions ofthe inks indicate the contents of the respective constituent componentsin terms of % by weight with respect to the whole amount of each inkcomposition. The colorant is added in the form of a dispersion.Accordingly, the amount of the colorant dispersion added is calculatedfrom the colorant content in the ink and from the solid concentration ofthe colorant dispersion.

Olfin E1010 (manufactured by Nisshin Chemical Industry), Olfin STG(manufactured by Nisshin Chemical Industry), and Surfynol 465(manufactured by Air Product) are acetylene glycol surfactants. Surfynol61 (manufactured by Air Product) is an acetylene alcohol surfactant.

The surface tension in Tables 1 to 31 below was measured with anautomatic surface tension balance, Model CBVP-Z manufactured by KyowaKaimen Gagaku.

The inks of the Examples all have ΔSP of at least 1.0 cal/cm³.

Regarding the colorants, the compounds of formula (1) and the compoundsof formula (2), the numeral in the upper row indicates the contentthereof, and the code in the lower row indicates the kind of thecolorant, the compound of formula (1) or the compound of formula (2).

Specifically, the codes of the compounds shown in the Tables are asfollows:

[1-1]: compound of formula (1), wherein R is neopentyl group, n is 1.0,m is 1.5, and M is hydrogen atom.

[1-2]: compound of formula (1), wherein R is t-butyl group, n is 1.0, mis 2.0, and M is hydrogen atom.

[1-3]: compound of formula (1), wherein R is 1,3-dimethylbutyl group, nis 0, m is 4.5, and M is hydrogen atom.

[1-4]: compound of formula (1), wherein R is isobutyl group, n is 3.0, mis 1.0, and M is hydrogen atom.

[1-5]: compound of formula (1), wherein R is a mixture of 50% n-hexylgroup and 50% 2-ethylhexyl group; n and m for n-hexyl are 4.0 and 1.0,respectively, and n and m for 2-ethylhexyl are 2.0 and 1.0,respectively; and M is potassium phosphate for both n-hexyl and2-ethylhexyl.

[1-6]: compound of formula (1), wherein R is 1,1-dimethylbutyl, n is7.0, m is 1.0, and M is sodium borate.

[1-7]: compound of formula (1), wherein R is a mixture of 50% cyclohexylgroup and 50% n-heptyl group; n, m and M for cyclohexyl are 9.0, 1.0 andsodium sulfonate, respectively; and n, m and M for n-heptyl are 3.5, 2.0and potassium phosphate, respectively.

[1-8]: compound of formula (1), wherein R is a mixture of is 50%neopentyl group, 30% n-pentyl group and 20% isopentyl group; n, m and Mfor neopentyl are 0, 1.0 and K⁺, respectively; n, m and M for n-pentylare 2.5, 1.0 and ammonium sulfonate, respectively; and n, m and M forisopentyl are 3.0, 1.5 and hydrogen atom, respectively.

[1-9]: compound of formula (1), wherein R is a mixture of 50% cyclohexylgroup and 50% n-heptyl group; k, m and M for cyclohexyl are 9.0, 1.0 andammonium borate, respectively; and k, m and M for n-heptyl are 3.5, 2.0and triethanolamine borate, respectively.

[1-10]: compound of formula (1), wherein R is a mixture of 50% n-hexylgroup and 50% 2-ethylhexyl group; n and m for n-hexyl are 4.0 and 1.0,respectively; n and m for 2-ethylhexyl are 2.0 and 1.0, respectively;and M is triethanolamine sulfonate for both h-hexyl and 2-ethylhexyl.

[1-11]: compound of formula (1), wherein R is a mixture of 50%cyclohexyl group and 50% n-heptyl group; n, m and M for cyclohexyl are9.0, 1.0 and potassium borate, respectively; and n, m and M for n-heptylare 3.5, 2.0 and ammonium borate, respectively.

[1-12]: compound of formula (1), wherein R is a mixture of 50% neopentylgroup, 30% n-pentyl group and 20% isopentyl group; n, m and M forneopentyl are 0, 1.0 and K⁺, respectively; n, m and M for n-pentyl are2.5, 1.0 and ammonium sulfonate, respectively; and n, m and M forisopentyl are 3.0, 1.5 and sodium phosphate, respectively.

[1-13]: compound of formula (1), wherein R is a mixture of 50% n-hexylgroup and 50% 2-ethylhexyl group; k and m for n-hexyl are 4.0 and 1.0,respectively; k and m for 2-ethylhexyl are 2.0 and 1.0, respectively;and M is potassium borate for both n-hexyl and 2-ethylhexyl.

[1-14]: compound of formula (1), wherein R is a mixture of 50% n-butylgroup and 50% n-heptyl group; k, m and M for n-butyl are 9.0, 1.0 andammonium phosphate, respectively; and k, m and M for n-heptyl are 3.5,2.0 and triethanolamine phosphate, respectively.

[1-15]: compound of formula (1), wherein R is a mixture of 50%cyclohexyl group and 50% n-heptyl group; k, m and M for cyclohexyl are9.0, 1.0 and ammonium borate, respectively; and k, m and M for n-heptylare 3.5, 2.0 and triethanolamine borate, respectively.

[1-16]: compound of formula (1), wherein R is neopentyl group, n is 1.0,m is 1.5, and M is sodium.

[1-17]: compound of formula (1), wherein R is t-butyl group, n is 1.0, mis 2.0, and M is triethanolamine.

[1-18]: compound of formula (1), wherein R is isobutyl group, n is 3.0,m is 1.0, and M is ammonia.

[1-19]: 1:1 mixture of compound of formula (1) wherein R is n-hexylgroup, n is 4.0 and m is 1.0 and compound of formula (1) wherein R is2-ethylhexyl group, n is 2.0 and m is 1.0, in both of which M ispotassium.

[1-20]: compound of formula (1), wherein R is a mixture of 50%cyclohexyl group and 50% n-heptyl group; n, m and M for cyclohexyl are9.0, 1.0 and hydrogen atom, respectively; and n, m and M for h-heptyl is3.5, 2.0 and sodium phosphate, respectively.

[1-21]: compound of formula (1), wherein R is a mixture of 50% neopentylgroup, 30% n-pentyl group and 20% isopentyl group; n, m and M forneopentyl are 0, 1.0 and K⁺, respectively; n, m and M for n-pentyl are2.5, 1.0 and ammonium borate, respectively; and n, m and M for isopentylare 3.0, 1.5 and hydrogen atom, respectively.

[1-22]: compound of formula (1), wherein R is a mixture of 50% n-hexylgroup and 50% 2-ethylhexyl group mixed; n and m for n-hexyl are 4.0 and1.0, respectively; n and m for 2-ethylhexyl are 2.0 and 1.0,respectively; and M is potassium sulfonate for both n-hexyl and2-ethylhexyl.

[1-23]: compound of formula (1), wherein R is a mixture of 50%cyclohexyl group and 50% n-heptyl group; n, m and M for cyclohexyl are9.0, 1.0 and hydrogen atom, respectively; n, m and M for n-heptyl are3.5, 2.0 and sodium phosphate, respectively.

[1-24]: compound of formula (1), wherein R is a mixture of 50% neopentylgroup, 30% n-pentyl group and 20% isopentyl group; n, m and M forneopentyl are 0, 1.0 and K⁺, respectively; n, m and M for n-pentyl are2.5, 1.0 and ammonium borate, respectively; and n, m and M for isopentylare 3.0, 1.5 and hydrogen atom, respectively.

[1-25]: compound of formula (1), wherein R is a mixture of 50%cyclohexyl group and 50% n-heptyl group; n, m and M for cyclohexyl are9.0, 1.0 and sodium borate, respectively; and n, m and M for n-heptylare 3.5, 2.0 and ammonium borate, respectively.

[2-1]: compound of formula (2), wherein n is 2, and EP is ethyleneoxyalone.

[2-2]: compound of formula (2), wherein n is 0.8, and EP is ethyleneoxyalone.

[2-3]: compound of formula (2), wherein n is 4, and EP is ethyleneoxyand propyleneoxy in a ratio of 3:1.

[2-4]: compound of formula (2), wherein n is 1.5, and EP is ethyleneoxyalone.

[2-5]: compound of formula (2), wherein n is 2.8, and EP is ethyleneoxyalone.

[2-6]: compound of formula (2), wherein n is 3.5, and EP is ethyleneoxyalone.

[2-7]: compound of formula (2), wherein n is 10, and EP is ethyleneoxyalone.

[2-8]: compound of formula (2), wherein n is 4.5, and EP is ethyleneoxyalone.

[2-9]: compound of formula (2), wherein n is 4, and EP is ethyleneoxyalone.

[2-10]: compound of formula (2), wherein n is 5, and EP is ethyleneoxyand propyleneoxy in a ratio of 3:1.

[2-11]: compound of formula (2), wherein n is 3, and EP is ethyleneoxyalone.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 colorant 7.5 4.55.5 5.0 7.5 4.5 5.5 5.0 1-1 1-2 1-3 1-4 1-1 1-2 1-3 1-4 Olfin E1010 1.00.5 Olfin STG 1.0 0.7 Surfynol 465 1.2 Surfynol 61 0.5 1.0 1.0 0.5 0.3DEGmBE 5.0 5.0 TEGmBE 10.0 5.0 4.0 PGmBE 1.0 1,2-pentanediol 2.01,2-hexanediol 3.0 5.0 3.0 5.0 5.0 1,6-hexanediol 5.0 glycerin 14.0 9.09.0 14.0 14.0 9.0 12.0 12.0 diethylene glycol 5.0 7.0 5.0 thiodiglycol3.5 3.5 trimethylolpropane 1.0 1,3-dimethyl-2-imidazolidinone 2.0 2.02.0 2.0 2.0 triethanolamine 0.8 0.9 1.0 0.7 0.9 0.9 potassium hydroxide0.1 0.1 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 water balancebalance balance balance balance balance balance balance surface tension(mN/m) 34 32 34 34 35 33 32 32

TABLE 2 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 Ex. 15 Ex. 16 Colorant7.0 7.0 7.5 4.5 5.5 7.5 7.5 5.5 1-1 1-1 1-1 1-2 1-3 1-1 1-1 1-1 OlfinE1010 1.0 1.0 Olfin STG 1.0 1.0 Surfynol 465 0.5 1.2 Surfynol 61 0.6DEGmBE 4.0 2.5 7.0 TEGmBE 5.0 8.0 PGmBE 2.0 DPGmBE 1.0 3.01,2-hexanediol 3.0 7.0 5.0 4.5 1.0 5.0 1,6-hexanediol 5.0 Glycerin 10.010.0 12.0 10.0 10.0 12.0 12.0 12.0 diethylene glycol 2.0 7.0tetraethylene glycol 5.0 Thiodiglycol 3.0 3.51,3-dimethyl-2-imidazolidinone 2.0 Triethanolamine 0.9 0.8 0.9 0.9 0.80.8 0.8 potassium hydroxide 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.030.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02Water balance balance balance balance balance balance balance balancesurface tension (mN/m) 30 32 33 33 32 33 35 34

TABLE 3 Ex. 17 Ex. 18 Ex. 19 Ex. 20 Ex. 21 Ex. 22 Ex. 23 Ex. 24 Colorant7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 1-1 1-1 1-1 1-1 1-1 1-1 1-1 1-5 OlfinE1010 1.0 1.0 Surfynol 61 0.5 0.5 DEGmBE 8.0 5.0 TEGmBE 5.0 3.0 PGmBE1.0 1,2-pentanediol 4.0 2.0 1,2-hexanediol 3.0 5.0 Glycerin 12.0 12.012.0 12.0 12.0 12.0 12.0 14.0 1,3-dimethyl-2-imidazolidinone 2.0 2.0 1.0Triethanolamine 0.8 0.8 0.8 0.8 0.8 0.8 potassium hydroxide 0.10 0.10Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.020.02 0.02 0.02 0.02 0.02 0.02 0.02 Water balance balance balance balancebalance balance balance balance surface tension (mN/m) 35 35 34 36 34 3136 34

TABLE 4 Ex. 25 Ex. 26 Ex. 27 Ex. 28 Ex. 29 Ex. 30 Ex. 31 Ex. 32 Colorant4.5 5.5 5.0 7.5 4.5 5.5 3.0 5.0 1-6 1-7 1-8 1-20 1-20 1-20 3-1 3-2 OlfinE1010 0.5 1.0 1.0 Olfin STG 1.0 0.5 1.0 Surfynol 465 1.2 1.2 Surfynol 610.5 DEGmBE 5.0 7.0 TEGmBE 10.0 5.0 10.0 6.0 PGmBE 2.0 1,2-pentanediol2.0 1,2-hexanediol 3.0 5.0 3.0 1.0 2.0 1,6-hexanediol 5.0 5.0 Glycerin9.0 9.0 14.0 10.0 9.0 9.0 14.0 15.0 diethylene glycol 5.0 7.0 5.0 7.0tetraethylene glycol 3.5 Thiodiglycol 3.5 1,3-dimethyl-2-imidazolidinone2.0 2.0 Triethanolamine 0.9 1.0 0.7 0.8 0.9 0.8 0.9 potassium hydroxide0.1 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Water balancebalance balance balance balance balance balance balance surface tension(mN/m) 32 34 31 33 32 32 32 34

TABLE 5 Ex. 33 Ex. 34 Ex. 35 Ex. 36 Colorant 5.0 5.5 5.0 5.5 3-3 3-4 3-43-4 Olfin E1010 1.0 Surfynol 465 1.0 Surfynol 61 0.5 1.0 DEGmBE 8.0 8.0TEGmBE 4.0 PGmBE 2.0 1,2-hexanediol 5.0 5.0 Glycerin 15.0 7.0 15.0 15.0diethylene glycol 5.0 tetrapropylene glycol 5.0 Trimethylolpropane 1.01.0 1,3-dimethyl-2-imidazolidinone 2.0 Triethanolamine 0.5 0.9 0.9 0.3potassium hydroxide 0.05 0.1 0.1 Proxel XL-2 0.03 0.03 0.03 0.03Benzotriazole 0.02 0.02 0.02 0.02 Water balance balance balance balancesurface tension (mN/m) 31 28 34 31

TABLE 6 Ex. 37 Ex. 38 Ex. 39 Ex. 40 Ex. 41 Ex. 43 Ex. 43 Ex. 44 Colorant4.0 3.0 4.0 3.0 4.0 3.0 4.0 3.0 4-1 4-2 4-1 4-2 4-1 4-2 4-1 4-2 OlfinE1010 1.0 0.5 Olfin STG 1.0 0.7 Surfynol 465 1.2 Surfynol 61 0.5 1.0 1.00.5 0.3 DEGmBE 5.0 5.0 TEGmBE 10.0 5.0 4.0 PGmBE 1.0 DPGmBE1,2-pentanediol 2.0 1,2-hexanediol 3.0 5.0 3.0 5.0 5.0 1,6-hexanediol5.0 Glycerin 14.0 9.0 9.0 14.0 14.0 9.0 12.0 12.0 diethylene glycol 5.07.0 5.0 tetraethylene glycol thiodiglycol 3.5 3.5 trimethylolpropane 1.01,3-dimethyl-2-imidazolidinone 2.0 2.0 2.0 2.0 2.0 triethanolamine 0.80.9 1.0 0.7 0.9 0.9 potassium hydroxide 0.1 0.1 0.1 Proxel XL-2 0.030.03 0.03 0.03 0.03 0.03 0.03 0.03 benzotriazole 0.02 0.02 0.02 0.020.02 0.02 0.02 0.02 Water balance balance balance balance balancebalance balance balance surface tension (mN/m) 34 32 34 34 35 33 32 32

TABLE 7 Ex. 45 Ex. 46 Ex. 47 Ex. 48 Ex. 49 Ex. 50 Ex. 51 Ex. 52 Colorant4.0 3.0 4.0 3.0 4.0 3.0 4.0 3.0 4-1 4-2 4-1 4-2 4-1 4-2 4-1 4-2 OlfinE1010 1.0 Olfin STG 1.0 Surfynol 465 0.5 Surfynol 61 0.5 0.5 0.3 DEGmBE4.0 8.0 TEGmBE 8.0 PGmBE 2.0 DPGmBE 1.0 1,2-pentanediol 4.01,2-hexanediol 3.0 7.0 5.0 1,6-hexanediol Glycerin 10.0 10.0 12.0 12.012.0 12.0 12.0 12.0 diethylene glycol 2.0 thiodiglycol 3.01,3-dimethyl-2-imidazolidinone 2.0 2.0 triethanolamine 0.9 0.8 0.8 0.80.8 0.8 0.8 potassium hydroxide 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.030.03 0.03 0.03 benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02Water balance balance balance balance balance balance balance balancesurface tension (mN/m) 30 32 33 35 34 35 35 34

TABLE 8 Ex. 53 Ex. 54 Ex. 55 Ex. 56 Colorant 4.0 3.0 7.0 7.0 4-1 4-2 6-16-1 Olfin E1010 1.0 Olfin STG 1.0 DEGmBE 3.0 2.0 TEGmBE 5.0 1.0 PGmBE1.0 1,2-pentanediol 2.0 2.0 1,2-hexanediol 3.0 2.0 Glycerin 12.0 12.012.0 12.0 1,3-dimethyl-2-imidazolidinone 2.0 triethanolamine 0.8 0.8 0.50.9 potassium hydroxide 0.1 Proxel XL-2 0.03 0.03 0.03 0.03benzotriazole 0.02 0.02 0.02 0.03 Water balance balance balance balancesurface tension (mN/m) 36 34 33 29

TABLE 9 Ex. 57 Ex. 58 Ex. 59 Ex. 60 Ex. 61 Ex. 62 Ex. 63 Ex. 64 Colorant7.5 4.5 5.5 5.5 5.0 7.5 4.5 5.5 1-1 1-2 1-3 1-3 1-4 1-1 1-2 1-3 OlfinE1010 1.0 0.5 Olfin STG 1.0 1.0 Surfynol 465 1.2 Surfynol 61 0.5 1.0 1.00.5 DEGmBE 2.5 7.0 5.0 TEGmBE 5.0 5.0 4.0 PGmBE 1.0 DPGmBE 3.01,2-pentanediol 2.0 1,2-hexanediol 4.5 1.0 5.0 3.0 5.0 1,6-hexanediol5.0 5.0 Glycerin 12.0 10.0 7.0 7.0 10.0 10.0 7.0 10.0 Maltitol 3.5 2.5Maltose 3.0 erythritol 2.5 Isomalto-oligosaccharide 2.0 Sorbitol 3.0Fructose 3.0 Xylitol 5.0 Glucose 3.0 Xylose 5.0 diethylene glycol 7.05.0 thiodiglycol 3.5 3.5 3.5 1,3-dimethyl-2-imidazolidinone 2.0 2.0 2.02.0 triethanolamine 0.8 0.9 1.0 1.0 0.7 0.9 potassium hydroxide 0.1 0.10.1 0.10 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Water balancebalance balance balance balance balance balance balance surface tension(mN/m) 34 34 31 35 35 36 34 33

TABLE 10 Ex. 65 Ex. 66 Ex. 67 Ex. 68 Ex. 69 Ex. 70 Ex. 71 Ex. 72Colorant 5.0 7.0 7.0 7.5 7.5 7.5 7.5 7.5 1-4 1-1 1-1 1-1 1-1 1-1 1-1 1-1Olfin E1010 1.0 Olfin STG 0.7 1.0 Surfynol 465 0.5 Surfynol 61 0.3 0.50.5 DEGmBE 4.0 8.0 TEGmBE 8.0 PGmBE 2.0 DPGmBE 1.0 1,2-hexanediol 5.03.0 7.0 5.0 Glycerin 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 Maltitol1.0 2.5 1.0 2.0 Maltose 3.0 2.0 Erythritol 2.0 Mannitol 2.0 1.0 Sorbitol2.0 3.0 Fructose 2.0 Xylitol 2.5 1.0 Xylose 3.0 4.0 diethylene glycol2.0 Thiodiglycol 3.0 Trimethylolpropane 1.01,3-dimethyl-2-imidazolidinone 2.0 2.0 2.0 Triethanolamine 0.9 0.9 0.80.8 0.8 0.8 0.8 potassium hydroxide 0.1 Proxel XL-2 0.03 0.03 0.03 0.030.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.020.02 Water balance balance balance balance balance balance balancebalance surface tension (mN/m) 33 31 33 34 36 35 36 38

TABLE 11 Ex. 73 Ex. 74 Ex. 75 Ex. 76 Ex. 77 Ex. 78 Ex. 79 Ex. 80Colorant 7.5 7.5 7.5 7.5 7.5 7.5 4.5 5.5 1-1 1-1 1-1 1-1 1-1 1-5 1-6 1-7Olfin E1010 1.0 1.0 Olfin STG 1.0 Surfynol 465 1.2 Surfynol 61 0.5DEGmBE 6.0 TEGmBE 5.0 3.0 10.0 PGmBE 1.0 1,2-pentanediol 4.0 2.01,2-hexanediol 3.0 5.0 3.0 5.0 1,6-hexanediol 5.0 Glycerin 10.0 10.010.0 10.0 10.0 10.0 9.0 9.0 Maltitol 2.0 2.0 2.0 Maltose 1.0 Erythritol1.0 isomalto-oligosaccharide 1.0 1.0 Sorbitol 4.0 1.0 1.0 Xylitol 4.02.0 2.0 1.0 Xylose 2.0 1.0 diethylene glycol 5.0 7.0 Thiodiglycol 3.51,3-dimethyl-2-imidazolidinone 2.0 1.0 2.0 Triethanolamine 0.8 0.8 0.80.8 0.9 1.0 potassium hydroxide 0.10 0.10 0.1 Proxel XL-2 0.03 0.03 0.030.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.020.02 0.02 Water balance balance balance balance balance balance balancebalance surface tension (mN/m) 35 37 35 32 37 35 33 35

TABLE 12 Ex. 81 Ex. 82 Ex. 83 Ex. 84 Ex. 85 Ex. 86 Ex. 87 Colorant 5.03.0 5.0 5.0 5.5 5.0 5.0 1-8 3-1 3-2 3-3 3-4 3-2 3-3 Olfin E1010 0.5 1.01.0 Olfin STG 1.0 Surfynol 465 1.0 Surfynol 61 0.5 0.5 1.0 DEGmBE 7.08.0 8.0 TEGmBE 5.0 6.0 4.0 PGmBE 2.0 2.0 1,2-pentanediol 2.01,2-hexanediol 3.0 2.0 5.0 5.0 Glycerin 10.0 11.0 11.0 11.0 7.0 10.010.0 Maltitol 1.0 1.0 2.0 2.0 Maltose 1.0 2.0 Erythritol 1.0 1.0isomalto-oligosaccharide 1.0 1.0 Sorbitol 1.0 2.0 2.0 Fructose 1.0 2.0Xylitol 1.0 2.0 Xylose 2.0 diethylene glycol 5.0 tetrapropylene glycol5.0 Trimethylolpropane 1.0 1.0 1,3-dimethyl-2-imidazolidinone 2.0 2.0Triethanolamine 0.7 0.9 0.5 0.8 0.9 0.3 potassium hydroxide 0.1 0.05 0.10.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.020.02 0.02 0.02 0.02 0.02 0.02 Water balance balance balance balancebalance balance balance surface tension (mN/m) 32 33 35 32 30 35 32

TABLE 13 Ex. 88 Ex. 89 Ex. 90 Ex. 91 Ex. 92 Ex. 93 Ex. 94 Ex. 95Colorant 4.0 3.0 4.0 3.0 4.0 3.0 4.0 3.0 4-1 4-2 4-1 4-2 4-1 4-2 4-1 4-2Olfin E1010 1.0 0.5 Olfin STG 1.0 0.7 Surfynol 465 1.2 Surfynol 61 0.51.0 1.0 0.5 0.3 DEGmBE 5.0 5.0 TEGmBE 10.0 5.0 4.0 PGmBE 1.01,2-pentanediol 2.0 1,2-hexanediol 3.0 5.0 3.0 5.0 5.0 1,6-hexanediol5.0 Glycerin 10.0 7.0 7.0 12.0 12.0 7.0 10.0 10.0 Maltitol 3.5 2.5Maltose 3.0 Erythritol 2.5 isomalto-oligosaccharide 2.0 Sorbitol 3.0Fructose 3.0 Xylitol 5.0 Glucose 3.0 Xylose 5.0 diethylene glycol 5.07.0 5.0 Thioglycol 3.5 3.5 Trimethylolpropane 1.01,3-dimethyl-2-imidazolidinone 2.0 2.0 2.0 2.0 2.0 Triethanolamine 0.80.9 1.0 0.7 0.9 0.9 potassium hydroxide 0.1 0.1 0.1 Proxel XL-2 0.030.03 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.020.02 0.02 0.02 0.02 Water balance balance balance balance balancebalance balance balance surface tension (mN/m) 35 33 35 35 36 34 33 33

TABLE 14 Ex. Ex. Ex. Ex. Ex. 96 Ex. 97 Ex. 98 Ex. 99 100 101 102 103Colorant 4.0 3.0 4.0 3.0 4.0 3.0 4.0 3.0 4-1 4-2 4-1 4-2 4-1 4-2 4-1 4-2Olfin E1010 1.0 Olfin STG 1.0 Surfynol 465 0.5 Surfynol 61 0.5 0.5DEGmBE 4.0 8.0 TEGmBE 8.0 PGmBE 2.0 DPGmBE 1.0 1,2-pentanediol 4.01,2-hexanediol 3.0 7.0 5.0 1,6-hexanediol Glycerin 8.0 8.0 10.0 10.010.0 10.0 10.0 10.0 Maltitol 1.0 2.5 1.0 2.0 Maltose 3.0 2.0 Erythritol2.0 isomalto-oligosaccharide Mannitol 2.0 1.0 Sorbitol 2.0 3.0 Fructose2.0 Xylitol 2.5 1.0 Glucose Xylose 3.0 4.0 diethylene glycol Thioglycol3.0 Trimethylolpropane 1,3-dimethyl-2-imidazolidinone 2.0 2.0Triethanolamine 0.9 0.8 0.8 0.8 0.8 0.8 0.8 potassium hydroxide 0.1Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.020.02 0.02 0.02 0.02 0.02 0.02 0.02 Water balance balance balance balancebalance balance balance balance surface tension (mN/m) 31 33 34 36 35 3636 35

TABLE 15 Ex. 104 Ex. 105 Ex. 106 Colorant 4.0 3.0 7.0 4-1 4-2 6-1Surfynol 465 1.0 TEGmBE 5.0 3.0 PGmBE 1.0 1,2-pentanediol 2.01,2-hexanediol 3.0 3.0 Glycerin 10.0 10.0 12.0 Maltitol 3.0 Sorbitol 4.0Xylitol 4.0 3.0 1,3-dimethyl-2-imidazolidinone 2.0 Triethanolamine 0.80.8 0.5 potassium hydroxide 0.1 Proxel XL-2 0.03 0.03 0.03 Benzotriazole0.02 0.02 0.02 Water balance balance balance surface tension (mN/m) 3735 33

TABLE 16 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 107 108 109 110 111 112 113 114Colorant 7.5 4.5 5.5 5.0 3.0 5.0 5.0 5.5 1-1 1-2 1-3 1-4 3-1 3-2 3-3 3-4Olfin E1010 1.0 1.0 Olfin STG 0.5 1.0 Surfynol 465 1.2 1.0 Surfynol 610.5 0.5 DEGmBE 7.0 8.0 10.0 TEGmBE 3.0 6.0 PGmBE 2.0 DPGmBE 2.0 DPDmBE2.0 1,2-pentanediol 5.0 1,2-hexanediol 1.0 compound of formula (1) 5.010.0 10.0 8.0 7.0 6.0 10.0 6.0 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 Glycerin9.0 14.0 15.0 15.0 7.0 diethylene glycol 7.0 5.0 dipropylene glycol 5.0tetraethylene glycol 9.0 tetrapropylene glycol 5.0 Thiodiglycol 3.5 2.0Trimethylolpropane 1.0 Maltitol 1.0 1,3-dimethyl-2-imidazolidinone 2.0Triethanolamine 0.8 0.9 1.0 0.7 0.9 0.9 0.5 0.9 potassium hydroxide 0.10.1 0.05 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Water balancebalance balance balance balance balance balance balance surface tension(mN/m) 32 32 32 34 31 32 32 31

TABLE 17 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 115 116 117 118 119 120 121 122Colorant 7.5 4.5 5.5 5.0 3.0 5.0 5.0 5.5 1-1 1-2 1-3 1-4 3-1 3-2 3-3 3-4Olfin E1010 1.0 1.0 Olfin STG 3.5 1.0 Surfynol 465 1.2 1.0 Surfynol 610.5 0.5 DEGmBE 2.5 7.0 7.0 8.0 10.0 TEGmBE 5.0 3.0 6.0 PGmBE 2.0 DPGmBE3.0 2.0 DPDmBE 3.0 2.0 1,2-propanediol 6.0 1,2-pentanediol 5.01,2-hexanediol 4.5 1.0 compound of formula (1) 8.0 7.0 10.0 6.0 1-4 1-51-9 1-8 1,5-pentanediol 5.0 2.0 1.0 Glycerin 9.0 8.0 7.0 8.0 14.0 10.010.0 7.0 compound of formula (2) 8.0 10.0 2.0 8.0 10.0 6.0 10.0 6.0 2-12-2 2-3 2-4 2-5 2-6 2-7 2-8 Maltose 3.0 diethylene glycol 5.0dipropylene glycol 5.0 tetraethylene glycol 1.0 Trimethylolpropane 2.01,3-dimethyl-2-imidazolidinone 2.0 Triethanolamine 0.8 0.9 1.0 0.7 0.90.9 0.5 0.9 potassium hydroxide 0.1 0.05 0.1 Proxel XL-2 0.03 0.03 0.030.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.020.02 0.02 Water balance balance balance balance balance balance balancebalance surface tension (mN/m) 33 32 31 34 34 32 33 29

TABLE 18 Ex. Ex. Ex. Ex. 123 124 125 126 Colorant 5.0 3.0 5.0 5.5 1-43-1 3-3 3-4 Olfin STG 1.0 Surfynol 465 0.5 1.0 Surfynol 61 0.5 DEGmBE7.0 8.0 10.0 TEGmBE 3.0 PGmBE 2.0 2.0 1,2-pentanediol 5.0 compound offormula (1) 8.0 7.0 10.0 6.0 1-4 1-10 1-11 1-12 1,5-pentanediol 2.0Glycerin 8.0 14.0 10.0 7.0 Maltose 5.0 erythritol 1.0 mannitol 3.0Sorbitol 2.0 Fructose 2.0 3.0 Xylitol 2.5 Xylose 2.0 diethylene glycol5.0 tetraethylene glycol 1.0 tetrapropylene glycol 5.0trimethylolpropane 1.0 trimethylolethane 1.01,3-dimethyl-2-imidazolidinone 2.0 sodium benzoate 0.1 triethanolamine0.7 0.9 0.5 0.9 potassium hydroxide 0.05 0.1 Proxel XL-2 0.03 0.03 0.030.03 benzotriazole 0.02 0.02 0.02 0.02 Water balance balance balancebalance surface tension (mN/m) 34 34 33 33

TABLE 19 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 127 128 129 130 131 132 133 134Colorant 7.5 4.5 5.5 5.0 3.0 5.0 5.0 5.5 1-1 1-2 1-3 1-4 1-1 1-2 1-3 1-4Olfin E1010 1.0 1.0 Olfin STG 0.5 1.0 Surfynol 465 1.2 1.0 Surfynol 610.5 0.5 DEGmBE 2.5 7.0 7.0 8.0 10.0 TEGmBE 5.0 3.0 6.0 PGmBE 2.0 DPGmBE2.0 DPDmBE 3.0 1,2-propanediol 6.0 1,2-pentanediol 5.0 1,2-hexanediol4.5 1.0 1,5-pentanediol 5.0 1,6-hexanediol 5.0 Glycerin 9.0 8.0 7.0 8.014.0 7.0 10.0 7.0 compound of formula (2) 3.0 2.0 3.0 2-9 2-10 2-11Maltitol 2.5 Maltose 3.5 3.0 3.0 5.0 Erythritol 2.5isomalto-oligosaccharide 2.0 1.0 Mannitol 3.0 Sorbitol 2.0 Fructose 2.03.0 Xylitol 2.5 Glucose 2.0 Xylose 2.0 diethylene glycol 7.0 5.0dipropylene glycol 5.0 tetraethylene glycol 1.0 tetrapropylene glycol5.0 Thiodiglycol 3.5 2.0 Trimethylolpropane 1.0 Trimethylolethane 1.01,3-dimethyl-2-imidazolidinone 2.0 Triethanolamine 0.8 0.9 1.0 0.7 0.90.9 0.5 0.9 potassium hydroxide 0.1 0.5 0.1 Proxel XL-2 0.03 0.03 0.030.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.020.02 0.02 Water balance balance balance balance balance balance balancebalance surface tension (mN/m) 33 32 31 34 34 32 32 29

TABLE 20 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 135 136 137 138 139 140 141 142Colorant 7.5 4.5 5.5 5.0 3.0 5.0 5.0 5.0 1-1 1-2 1-3 1-4 3-1 3-2 3-3 3-4Olfin E1010 0.1 0.05 Olfin STG 0.5 0.05 Surfynol 465 0.1 1.0 Surfynol 610.05 DEGmBE 0.5 0.7 0.3 0.5 TEGmBE 1.0 0.5 0.6 DPGmBE 0.3 DPDmBE 0.3DPGmME 1.5 TEGmME 1.5 1,2-propanediol 0.6 1,2-pentanediol 5.01,2-hexanediol 0.5 0.5 compound of formula (1) 0.5 0.5 0.5 0.8 1-4 1-51-15 1-18 1,5-pentanediol 5.0 2.0 1.0 Glycerin 9.0 8.0 7.0 8.0 14.0 10.010.0 7.0 compound of formula (2) 8.0 10.0 2.0 8.0 10.0 6.0 10.0 6.0 2-12-2 2-3 2-4 2-5 2-6 2-7 2-8 Maltitol 3.5 Maltose 3.0 diethylene glycol5.0 dipropylene glycol 5.0 tetraethylene glycol 1.0 Trimethylolpropane1.0 Trimethylolethane 1.0 1,3-dimethyl-2-imidazolidinone 2.0Triethanolamine 0.8 0.9 1.0 0.7 0.9 0.9 0.5 0.9 potassium hydroxide 0.10.05 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Water balancebalance balance balance balance balance balance balance surface tension(mN/m) 42 39 40 42 44 45 41 40

TABLE 21 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 143 144 145 146 147 148 149 150Colorant 7.5 7.5 4.5 5.5 5.0 7.5 7.5 7.5 1-9 1-10 1-11 1-12 1-13 1-141-15 1-16 Olfin E1010 1.0 1.0 1.0 1.0 1.0 Olfin STG 0.5 Surfynol 465 1.2Surfynol 61 0.5 TEGmBE 3.0 1,2-pentanediol 5.0 1,2-hexanediol 1.0compound of formula (1) 5.0 5.0 10.0 10.0 8.0 5.0 5.0 5.0 1-16 1-17 1-31-18 1-19 1-16 1-16 1-16 1,5-pentanediol 5.0 5.0 2.0 5.0 5.0 5.01,6-hexanediol 5.0 Glycerin 9.0 9.0 9.0 9.0 9.0 diethylene glycol 7.0dipropylene glycol 5.0 tetraethylene glycol 9.0 Thiodiglycol 3.51,3-dimethyl-2-imidazolidinone 2.0 Triethanolamine 0.8 0.8 0.9 1.0 0.70.8 0.8 0.8 potassium hydroxide 0.1 Water balance balance balancebalance balance balance balance balance surface tension (mN/m) 32 32 3130 33 32 32 32

TABLE 22 Ex. Ex. Ex. Ex. Ex. 151 152 153 154 155 Colorant 5.0 5.0 5.05.0 5.0 2-1 2-2 5-1 2-3 2-4 Olfin E1010 1.0 1.0 1.0 Surfynol 465 1.0 1.0DEGmBE 5.0 5.0 TEGmBE 5.0 5.0 5.0 PGmBE 3.0 DPGmBE 2.0 2.01,2-pentanediol 5.0 1,2-hexanediol 5.0 5.0 5.0 5.0 Glycerin 10.0 10.010.0 10.0 10.0 Triethanolamine 0.5 0.5 0.5 0.5 0.5 potassium hydroxide0.1 0.1 0.1 0.10 0.10 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 Benzotriazole0.02 0.02 0.02 0.02 0.02 Water balance balance balance balance balancesurface tension (mN/m) 32 32 32 32 32

TABLE 23 Ex. Ex. Ex. Ex. 156 157 158 159 Colorant 8.0 8.0 8.0 8.0 2-62-7 2-8 2-9 Olfin E1010 1.0 1.0 1.0 1.0 DEGmBE 5.0 5.0 5.0 5.01,2-hexanediol 5.0 5.0 5.0 5.0 Glycerin 10.0 10.0 10.0 10.0Triethanolamine 0.5 0.5 0.5 0.5 potassium hydroxide 0.1 0.1 0.1 0.1Proxel XL-2 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 Waterbalance balance balance balance surface tension (mN/m) 30 29 30 29

TABLE 24 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 160 161 162 163 164 165 166 167Colorant 5.0 5.0 5.0 5.0 5.0 8.0 8.0 8.0 2-1 2-2 5-1 2-3 2-4 2-6 2-7 2-8Olfin E1010 1.0 1.0 1.0 1.0 1.0 1.0 Surfynol 465 1.0 1.0 DEGmBE 5.0 5.05.0 5.0 5.0 TEGmBE 5.0 5.0 5.0 PGmBE 3.0 DPGmBE 2.0 2.0 1,2-pentanediol5.0 1,2-hexanediol 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Glycerin 10.0 10.0 10.010.0 10.0 10.0 10.0 10.0 Maltitol 3.5 2.5 Maltose 3.0 Erythritol 2.5isomalto-oligosaccharide 2.0 Mannitol Sorbitol 3.0 Fructose 3.0 Xylitol5.0 Glucose 3.0 Xylose 5.0 Triethanolamine 0.5 0.5 0.5 0.5 0.5 0.5 0.50.5 potassium hydroxide 0.1 0.1 0.1 0.10 0.10 0.1 0.10 0.10 Proxel XL-20.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.020.02 0.02 0.02 0.02 0.02 Water balance balance balance balance balancebalance balance balance surface tension (mN/m) 33 33 33 33 33 31 30 31

TABLE 25 Ex. 168 Comp. 1 Comp. 2 Colorant 8.0 8.0 8.0 2-9 2-6 2-6 OlfinE1010 1.0 5.0 Olfin STG 5.0 DEGmBE 5.0 TEGmBE 5.0 1,2-hexanediol 5.0 8.0Glycerin 10.0 15.0 5.0 Maltitol 1.0 Mannitol 2.0 diethylene glycol 0.51,3-dimethyl-2-imidazolidinone 6.0 2-pyrrolidone 5.0 Triethanolamine 0.50.5 0.5 potassium hydroxide 0.1 0.1 0.1 Proxel XL-2 0.03 0.03 0.03Benzotriazole 0.02 0.02 0.02 Water balance balance balance surfacetension (mN/m) 30 51 23

TABLE 26 Ex. Ex. Ex. Ex. Ex. 169 170 171 172 173 Colorant 8.0 8.0 8.08.0 8.0 1-18 1-19 2-5 2-11 2-12 Olfin E1010 1.0 1.0 1.0 1.0 1.0 DEGmBE5.0 5.0 5.0 TEGmBE 2.0 2.0 2.0 6.0 6.0 DPGmBE 1.0 1,2-hexanediol 3.0 3.03.0 2.0 2.0 Glycerin 10.0 10.0 10.0 10.0 10.0 Triethanolamine 0.5 0.50.5 0.5 0.5 potassium hydroxide 0.1 0.1 0.1 0.1 0.1 Proxel XL-2 0.030.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 Water balancebalance balance balance balance surface tension (mN/m) 33 32 33 32 32

TABLE 27 Ex. Ex. Ex. Ex. Ex. Ex. 174 175 176 177 178 179 Colorant 7.05.0 7.0 7.0 7.0 7.0 1-17 2-1 2-11 2-10 2-13 2-15 Olfin E1010 1.0 1.0 1.01.0 Surfynol 465 1.0 1.0 DEGmBE 5.0 5.0 5.0 TEGmBE 5.0 5.0 5.0 PGmBE 1.01.0 1.0 1.0 DPGmBE 2.0 1,2-pentanediol 3.0 3.0 3.0 1.0 1,2-hexanediol3.0 3.0 2.0 Glycerin 10.0 10.0 10.0 10.0 10.0 10.0 Triethanolamine 0.50.5 0.5 0.5 0.5 0.5 potassium hydroxide 0.1 0.1 0.1 0.1 Proxel XL-2 0.030.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.02 0.02 0.02 0.02 0.02Water bal- bal- bal- bal- bal- bal- ance ance ance ance ance ancesurface tension (mN/m) 33 32 32 32 32 32

TABLE 28 Ex. Ex. Ex. Ex. Ex. Ex. 180 181 182 183 184 185 Colorant 7.07.0 5.0 7.0 7.0 7.0 1-18 1-19 2-5 2-12 2-14 2-16 Olfin E1010 1.0Surfynol 465 1.0 1.0 1.0 1.0 1.0 DEGmBE 5.0 5.0 5.0 TEGmBE 5.0 5.0 5.0PGmBE 1.0 1.0 2.0 2.0 DPGmBE 2.0 1,2-pentanediol 3.0 1.0 2.0 2.01,2-hexanediol 2.0 3.0 3.0 1.0 Glycerin 10.0 10.0 10.0 10.0 10.0 10.0Triethanolamine 0.5 0.5 0.5 0.5 0.5 0.5 potassium hydroxide 0.1 0.1 0.10.1 0.1 0.1 Proxel XL-2 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.020.02 0.02 0.02 0.02 0.02 Water bal- bal- bal- bal- bal- bal- ance anceance ance ance ance surface tension (mN/m) 33 32 31 32 33 33

TABLE 29 Ex. Ex. Ex. Ex. 186 187 188 189 Colorant 5.0 3.0 5.0 5.5 3-13-2 3-3  3-4  Olfin STG 1.0 Surfynol 465 1.0 Surfynol 61 0.5 0.5 DEGmBE7.0 8.0 10.0 TEGmBE 3.0 PGmBE 2.0 DPGmBE 2.0 1,2-pentanediol 5.0compound of formula (1) 8.0 7.0 10.0 6.0 1-4 1-5 1-20 1-211,5-pentanediol 2.0 Glycerin 14.0 15.0 7.0 diethylene glycol 5.0tetraethylene glycol 9.0 tetrapropylene glycol 5.0 trimethylolpropane1.0 trimethylolethane 1.0 1,3-dimethyl-2-imidazolidinone 2.0triethanolamine 0.7 0.9 0.5 0.9 potassium hydroxide 0.05 0.1 Proxel XL-20.03 0.03 0.03 0.03 benzotriazole 0.02 0.02 0.02 0.02 Water balancebalance balance balance surface tension (mN/m) 34 34 33 31

TABLE 30 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 190 191 192 193 194 195 196 197Colorant 7.5 4.5 5.5 5.0 1.0 5.0 5.0 5.5 1-21 1-22 1-23  1-24 3-5 3-63-7 3-8 Olfin E1010 1.0 1.0 Olfin STG 0.5 1.0 Surfynol 465 1.2 1.0Surfynol 61 0.5 0.5 DEGmBE 2.5 7.0 7.0 8.0 10.0 TEGmBE 5.0 3.0 6.0 PGmBE2.0 DPGmBE 2.0 DPDmBE 3.0 1,2-propanediol 6.0 1,2-pentanediol 5.01,2-hexanediol 4.5 1.0 compound of formula (1) 8.0 7.0 10.0 6.0 1-4 1-22  1-23  1-24 1,5-pentanediol 5.0 2.0 1.0 1,6-hexanediol 5.0Glycerin 9.0 14.0 15.0 15.0 7.0 diethylene glycol 7.0 5.0 dipropyleneglycol 5.0 5.0 tetraethylene glycol 9.0 Thiodiglycol 3.5 2.0Trimethylolpropane 1.0 Trimethylolethane 1.01,3-dimethyl-2-imidazolidinone 2.0 sodium benzoate 0.1 Triethanolamine0.8 0.9 1.0 0.7 0.9 0.9 0.5 0.9 potassium hydroxide 0.1 0.05 0.1 ProxelXL-2 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Benzotriazole 0.02 0.020.02 0.02 0.02 0.02 0.02 0.02 Water balance balance balance balancebalance balance balance balance surface tension (mN/m) 33 33 31 34 34 3332 32

TABLE 31 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 198 199 200 201 202 203 204 205Colorant 7.5 4.5 5.5 5.0 3.0 5.0 5.0 5.5 1-1 1-2 1-3 1-4 3-1 3-2 3-3 3-4Olfin E1010 1.0 1.0 Olfin STG 0.5 1.0 Surfynol 465 1.2 1.0 Surfynol 610.5 0.5 DEGmBE 2.5 7.0 7.0 8.0 10.0 TEGmBE 5.0 3.0 6.0 PGmBE 2.0 DPGmBE2.0 DPDmBE 3.0 1,2-propanediol 3.0 1,2-pentanediol 5.0 1,2-hexanediol4.5 1.0 3.0 compound of formula (1) 8.0 7.0 10.0 6.0 1-4 1-5 1-25 1-81,5-pentanediol 2.0 Glycerin 12.0 12.0 7.0 8.0 14.0 10.0 10.0 7.0Maltitol 3.5 2.5 3.0 5.0 Maltose 3.0 Erythritol 2.5 1.0isomalto-oligosaccharide 2.0 Mannitol 3.0 Sorbitol 2.0 Fructose 2.0 3.0Xylitol 5.0 Glucose 2.0 Xylose 2.0 diethylene glycol 7.0 5.0tetraethylene glycol 1.0 tetrapropylene glycol 5.0 Trimethylolpropane1.0 Trimethylolethane 1.0 1,3-dimethyl-2-imidazolidinone 2.0 sodiumbenzoate Triethanolamine 0.8 0.9 0.7 0.9 0.5 0.9 potassium hydroxide 0.10.1 0.1 0.05 0.1 Proxel XL-2 0.03 0.03 0.03 Proxel TN 0.04 Deniside CST0.01 Deniside CSA 0.01 Deniside C3 0.02 Deniside OMP 0.03 Microstat S5200.03 NS-BP 0.05 Benzotriazole 0.02 0.02 0.03 0.02 0.02 0.03dicyclohexylammonium nitrate 0.02 0.02 disodium salt of 0.03 0.03 0.030.03 0.03 0.02 ethylenediaminetetraacetic acid dipotassium salt of 0.030.02 ethylenediaminetetraacetic acid Water balance balance balancebalance balance balance balance balance surface tension (mN/m) 33 32 3134 34 33 33 32

In accordance with the compositions set forth below, inks of(Comparative Example 3) to (Comparative Example) 5 were prepared.

Comparative Example 3

Weight (%) Carbon black pigment 5.0 (mean particle size, 105 nm)Glycerin 10.0 Dispersant 3.0 Nonionic surfactant 1.0 Ion-exchanged waterbalance Carbon black pigment: Raven C (manufactured by Columbia Carbon)Nonionic surfactant: Noigen EA160 (manufactured by Daiichi KogyoSeiyaku) Dispersant: Joncryl 62 (manufactured by Johnson Polymer)

Comparative Example 4

Weight (%) Acid Blue 9 5.5 DEGmME 7.0 Diethylene glycol 10.02-Pyrrolidone 5.0 Ion-exchanged water balance

Comparative Example 5

Weight (%) Direct Black 154 2.5 Diethylene glycol 10.0 Nonionicsurfactant 1.0 Ion-exchanged water balance Nonionic surfactant: Epan 450(manufactured by Daiichi Kogyo Seiyaku)

Inks of Comparative Example 6 to Comparative Example 15 were prepared byadding, to the composition of Comparative Example 3, at least onecompound selected from acetylene glycol surfactants, acetylene alcoholsurfactants, glycol ethers and 1,2-alkylene glycols as shown in Table 32below.

TABLE 32 Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. 6 78 9 10 11 12 13 14 15 Olfin E1010 1 1 1 1 Olfin STG 0.5 0.5 1 0.5Surfynol 465 Surfynol 61 0.5 0.5 DEGmBE 5 5 6 10 TEGmBE 8 7 8 PGmBE 2DPGmBE 2 3 1,2-pentanediol 5 5 1,2-hexanediol 3 2 2

The inks of Examples and Comparative Examples were evaluated accordingto the tests set forth below.

<Evaluation 1: Print Quality>

Using an ink jet printer, MJ-930C (manufactured by Seiko Epson), each 24pieces of upper-case and lower-case alphabet letters were printed witheach ink on various kinds of paper set forth below. The printed letterswere visually observed, and evaluated according to the followingcriteria.

-   -   SA: No bleeding was found on every kind of paper, and the        printed density is high.    -   AA: No bleeding was found on every kind of paper, but the        printed density is lower than that of the SA-rank.    -   A: Some bleeding was found only on a few kinds of paper.    -   B: Some bleeding was found on every kind of paper.    -   C: Much bleeding was found on every kind of paper.

Used in the test were 12 kinds of paper: Conqueror paper, Favorit paper,Modo paper, Rapid Copy paper, Epson EPP paper, Xerox P paper, Xerox 4024paper, Xerox 10 paper, Neenha Bond paper, Ricopy 6200 paper, Yamayuripaper (regenerated paper) and Xerox R paper (regenerated paper).

<Evaluation 2: Water Resistance>

Onto the printed area of each printed matter obtained in the printquality test of evaluation 1, 1 ml of ion-exchanged water was dropped.The condition of the printed matter, 20 minutes after the drop, wasvisually observed, and was evaluated according to the followingcriteria.

A: No change was found in every kind of paper.

B: A little colorant bled out of the printed area, but the printedletters are still recognizable.

C: The colorant bled out of the printed area, making the outline of theprinted letters blurred and making it difficult to recognize the printedletters.

<Evaluation 3: Dispersion Stability (1)>

Each ink was put in a glass sample bottle (50 ml) and the bottle wassealed. The sealed bottle was stored at 60° C. for 2 weeks. Before andafter the storage, the viscosity of the ink was measured withRheometrics Scientific RFS2 at 20° C. and 150 sec⁻¹. The obtained datawas evaluated according to the following criteria.

SA: The viscosity change is smaller than ±0.02 mPa·s.

AA: The viscosity change ranges from ±0.02 to smaller than 0.05 mPa·s.

A: The viscosity change ranges from ±0.05 to smaller than 0.1 mPa·s.

B: The viscosity change ranges from ±0.1 to smaller than 0.3 mPa·s.

C: The viscosity change is ±0.3 mPa·s or more.

<Evaluation 4: Dispersion Stability (2)>

Each ink was put in a glass sample bottle (50 ml) and the bottle wassealed. The sealed bottle was stored at 60° C. for 2 weeks to seewhether a sediment or foreign substance is generated or not, and theresult was evaluated according to the following criteria.

A: Generation of sediments or foreign substance was not found.

B: Generation of sediments or foreign substance was found.

<Evaluation 5: Clogging Resistance Reliability (1)>

Each ink was filled in the head of an ink jet printer, MJ-930Cmanufactured by Seiko Epson, with which alphabet and numeral letterswere printed on paper continuously for 10 minutes. Thereafter, theprinter was stopped, and left at 40° C. and a humidity of 25% for 2weeks with no cap fitted thereto. After this suspension, the printer wasagain used to print alphabet and numeral letters. The number ofoperation times required until prints of the same quality as that of theprints before the suspension (the number of operation times forrecovery) was counted, and was evaluated according to the followingcriteria.

SA: Prints of the same quality as that before the suspension wereobtained with 0 to 1 recovery operation.

AA: Prints of the same quality as that before the suspension wereobtained with 2 to 3 recovery operations.

A: Prints of the same quality as that before the suspension wereobtained with 3 to 4 recovery operations.

B: Prints of the same quality as that before the suspension wereobtained with 5 to 6 recovery operations.

C: Prints of the same quality as that before the suspension could notobtained even with 7 recovery operations.

<Evaluation 6: Ejection Stability>

Using an ink jet printer, MJ-930C (manufactured by Seiko Epson),alphabet and numeral letters were continuously printed with each ink onXerox P paper. The printing condition such as dot deletion and deviationin the ink-landing position was visually observed, and was evaluatedaccording to the following criteria.

SA: Even after printing over 50000 sheets, neither dot deletion nordeviation in the ink-landing position was found.

AA: Dot deletion or deviation in the ink-landing position was found atthe number of printed sheets of from 10000 to less than 50000.

A: Dot deletion or deviation in the ink-landing position was found atthe number of printed sheets of from 1000 to less than 10000.

B: Dot deletion or deviation in the ink-landing position was found atthe number of printed sheets of from 100 to less than 1000.

C: Dot deletion or deviation in the ink-landing position was found atthe number of printed sheets of less than 100.

<Evaluation 7: Rubbing Resistance>

Using the head of an ink jet printer, MJ-930C manufactured by SeikoEpson, solid printing was carried out with each ink at 100% duty on anarea of 10 mm×10 mm of a superfine-exclusive glossy film manufactured bySeiko Epson. The printed film was then left for 1 hour at 25° C., andthen the printed area was rubbed with an aqueous yellow fluorescent inkpen, ZEBRA PEN2 (trademark) manufactured by Zebra, under a load of 500 gat a speed of 10 mm/sec. The printed film was observed to see thepresence or absence of stains therein, and the result was evaluatedaccording to the following criteria.

A: Not stained at all, even after rubbed twice.

B: Not stained after rubbed once, but stained after rubbed twice.

C: Stained when rubbed once.

<Evaluation 8: Rapid Dryability>

Using an ink jet printer, MJ-930C (manufactured by Seiko Epson), solidprinting was carried out with each ink at 100% duty on an area of 10mm×10 mm of Xerox P paper. 10 seconds after the solid printing, a freshsheet of the same kind paper was put on the printed area, and a 300 gweight was put thereon. After kept as such for 10 seconds, the weightwas removed, and the latter fresh sheet was checked for the presence orabsence of ink transfer thereto. The result was evaluated according tothe following criteria.

A: No ink transfer was found.

B: Ink transfer was found.

TABLE 33 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 1 2 3 45 6 7 8 9 10 11 12 13 14 Print Quality SA SA SA SA SA SA SA SA SA SA SASA SA SA Water resistance A A A A A A A A A A A A A A DispersionStability (1) SA SA SA SA SA SA SA SA SA SA SA SA SA SA DispersionStability (2) A A A A A A A A A A A A A A Clogging Resistance AA AA AAAA AA AA AA AA AA AA AA AA AA AA Reliability (1) Jetting Stability SA SASA SA SA SA SA SA SA SA SA SA SA SA Rubbing Resistance A A A A A A A A AA A A A A Rapid Dryability A A A A A A A A A A A A A A

TABLE 34 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 15 1617 18 19 20 21 22 23 24 25 26 27 28 Print Quality SA SA SA SA SA SA SASA SA SA SA SA SA SA Water resistance A A A A A A A A A A A A A ADispersion Stability (1) SA SA SA SA SA SA SA SA SA SA SA SA SA SADispersion Stability (2) A A A A A A A A A A A A A A Clogging ResistanceAA AA AA AA AA AA AA AA AA AA AA AA AA AA Reliability (1) JettingStability AA AA SA AA AA AA AA SA AA SA SA SA SA SA Rubbing Resistance AA A A A A A A A A A A A A Rapid Dryability A A A A A A A A A A A A A A

TABLE 35 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 29 3031 32 33 34 35 36 37 38 39 40 41 42 Print Quality SA SA AA AA AA AA AAAA AA AA AA AA AA AA Water resistance A A A A A A A A A A A A A ADispersion Stability (1) SA SA SA SA SA SA SA SA A A A A A A DispersionStability (2) A A A A A A A A A A A A A A Clogging Resistance AA AA AAAA AA AA AA AA A A A A A A Reliability (1) Jetting Stability SA SA AA AAAA AA AA AA A A A A A A Rubbing Resistance A A A A A A A A A A A A A ARapid Dryability A A A A A A A A A A A A A A

TABLE 36 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 43 4445 46 47 48 49 50 51 52 53 54 55 56 Print Quality AA AA AA AA A A A A AA A A AA AA Water resistance A A A A A A A A A A A A A A DispersionStability (1) A A A A A A A A A A A A AA AA Dispersion Stability (2) A AA A A A A A A A A A A A Clogging Resistance A A A A A A A A A A A A A AReliability (1) Jetting Stability A A A A A A A A A A A A AA AA RubbingResistance A A A A A A A A A A A A A A Rapid Dryability A A A A A A A AA A A A A A

TABLE 37 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 57 5859 60 61 62 63 64 65 66 67 68 69 70 Print Quality SA SA SA SA SA SA SASA SA SA SA SA SA SA Water resistance A A A A A A A A A A A A A ADispersion Stability (1) SA SA SA SA SA SA SA SA SA SA SA SA SA SADispersion Stability (2) A A A A A A A A A A A A A A Clogging ResistanceSA SA SA SA SA SA SA SA SA SA SA SA SA SA Reliability (1) JettingStability SA SA SA SA SA SA SA SA SA SA SA SA AA AA Rubbing Resistance AA A A A A A A A A A A A A Rapid Dryability A A A A A A A A A A A A A A

TABLE 38 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 71 7273 74 75 76 77 78 79 80 81 82 83 84 Print Quality SA SA SA SA SA SA SASA SA SA SA AA AA AA Water resistance A A A A A A A A A A A A A ADispersion Stability (1) SA SA SA SA SA SA SA SA SA SA SA SA SA SADispersion Stability (2) A A A A A A A A A A A A A A Clogging ResistanceSA SA SA SA SA SA SA SA SA SA SA SA SA SA Reliability (1) JettingStability SA AA AA AA AA SA AA SA SA SA SA AA AA AA Rubbing Resistance AA A A A A A A A A A A A A Rapid Dryability A A A A A A A A A A A A A A

TABLE 39 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 85 8687 88 89 90 91 92 93 94 95 96 97 98 Print Quality AA AA AA AA AA AA AAAA AA AA AA AA AA A Water resistance A A A A A A A A A A A A A ADispersion Stability (1) SA SA SA A A A A A A A A A A A DispersionStability (2) A A A A A A A A A A A A A A Clogging Resistance SA SA SAAA AA AA AA AA AA AA AA AA AA AA Reliability (1) Jetting Stability AA AAAA A A A A A A A A A A A Rubbing Resistance A A A A A A A A A A A A A ARapid Dryability A A A A A A A A A A A A A A

TABLE 40 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 99 100101 102 103 104 105 106 107 108 109 110 111 112 Print Quality A A A A AA A AA SA SA SA SA AA AA Water resistance A A A A A A A A A A A A A ADispersion Stability (1) A A A A A A A AA SA SA SA SA SA SA DispersionStability (2) A A A A A A A A A A A A A A Clogging Resistance AA AA AAAA AA AA AA AA AA AA AA AA AA AA Reliability (1) Jetting Stability A A AA A A A AA SA SA SA SA AA AA Rubbing Resistance A A A A A A A A A A A AA A Rapid Dryability A A A A A A A A A A A A A A

TABLE 41 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 113 114 115 116117 118 119 120 121 122 123 124 Print Quality AA AA SA SA SA SA AA AA AAAA SA AA Water resistance A A A A A A A A A A A A Dispersion Stability(1) SA SA SA SA SA SA SA SA SA SA SA SA Dispersion Stability (2) A A A AA A A A A A A A Clogging Resistance AA AA SA SA SA SA SA SA SA SA SA SAReliability (1) Jetting Stability AA AA SA SA SA SA SA SA SA SA SA AARubbing Resistance A A A A A A A A A A A A Rapid Dryability A A A A A AA A A A A A

TABLE 42 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 125 126 127128 129 130 131 132 133 134 135 136 137 Print Quality AA AA SA SA SA SASA SA SA SA SA SA SA Water resistance A A A A A A A A A A A A ADispersion Stability (1) SA SA SA SA SA SA SA SA SA SA SA SA SADispersion Stability (2) A A A A A A A A A A A A A Clogging ResistanceSA AA SA SA SA SA SA SA SA SA SA SA SA Reliability (1) Jetting StabilityAA AA SA SA SA SA SA SA SA SA SA SA SA Rubbing Resistance A A A A A A AA A A A A A Rapid Dryability A A A A A A A A A A A A A

TABLE 43 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 138 139140 141 142 143 144 145 146 147 148 149 150 151 Print Quality SA AA AAAA AA SA SA SA SA SA SA SA SA AA Water resistance A A A A A A A A A A AA A A Dispersion Stability (1) SA SA SA SA SA SA SA SA SA SA SA SA SA AADispersion Stability (2) A A A A A A A A A A A A A A Clogging ResistanceSA SA SA SA SA AA AA AA AA AA AA AA AA A Reliability (1) JettingStability SA AA AA AA AA SA SA SA SA SA SA SA SA AA Rubbing Resistance AA A A A A A A A A A A A A Rapid Dryability A A A A A A A A A A A A A A

TABLE 44 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 152 153154 155 156 157 158 159 160 161 162 163 164 165 Print Quality AA AA AAAA SA SA SA SA AA AA AA AA AA SA Water resistance A A A A A A A A A A AA A A Dispersion Stability (1) AA AA AA AA SA SA SA SA AA AA AA AA AA SADispersion Stability (2) A A A A A A A A A A A A A A Clogging ResistanceA A A A SA SA SA SA AA AA AA AA AA SA Reliability (1) Jetting StabilityAA AA AA AA SA SA SA SA AA AA AA AA AA SA Rubbing Resistance A A A A A AA A A A A A A A Rapid Dryability A A A A A A A A A A A A A A

TABLE 45 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 166 167 168 Comp. 1 Comp. 2169 170 171 172 173 174 Print Quality SA SA SA AA B SA SA AA SA SA SAWater resistance A A A A A A A A A A A Dispersion Stability (1) SA SA SASA AA SA SA A SA SA SA Dispersion Stability (2) A A A A A A A A A A AClogging Resistance SA SA SA SA AA AA AA A AA AA AA Reliability (1)Jetting Stability SA SA SA AA C SA SA A SA SA SA Rubbing Resistance A AA A A A A A A A A Rapid Dryability A A A B A A A A A A A

TABLE 46 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 175 176 177 178 179180 181 182 183 184 185 Print Quality AA SA SA SA SA SA SA SA SA SA SAWater resistance A A A A A A A A A A A Dispersion Stability (1) A SA SASA SA SA SA SA SA SA SA Dispersion Stability (2) A A A A A A A A A A AClogging Resistance A AA AA AA AA AA AA AA AA AA AA Reliability (1)Jetting Stability AA SA SA SA SA SA SA A SA SA SA Rubbing Resistance A AA A A A A A A A A Rapid Dryability A A A A A A A A A A A

TABLE 47 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 186 187 188189 190 191 192 193 194 195 196 197 198 Print Quality SA AA AA AA SA SASA SA AA AA AA AA SA Water resistance A A A A A A A A A A A A ADispersion Stability (1) SA SA SA SA SA SA SA SA SA SA SA SA SADispersion Stability (2) A A A A A A A A A A A A A Clogging ResistanceAA AA AA AA AA AA AA AA AA AA AA AA AA Reliability (1) Jetting StabilityAA AA AA AA SA SA SA SA AA AA AA AA SA Rubbing Resistance A A A A A A AA A A A A A Rapid Dryability A A A A A A A A A A A A A

TABLE 48 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Comp. Comp. Comp Comp. Comp. Comp.199 200 201 202 203 204 205 3 4 5 6 7 8 Print Quality SA SA SA AA AA AAAA C C C B B B Water resistance A A A A A A A A C C A A A DispersionStability (1) SA SA SA SA SA SA SA C — — C C C Dispersion Stability (2)A A A A A A A B — — B B B Clogging Resistance AA AA AA AA AA AA AA C A AC C C Reliability (1) Jetting Stability SA SA SA AA AA AA AA C C C C C CRubbing Resistance A A A A A A A C C C C C C Rapid Dryability A A A A AA A B A B A A A

TABLE 49 Comp. Comp. Comp. Comp. Comp. Comp. Comp. 9 10 11 12 13 14 15Print Quality B B B B B B B Water resistance A A A A A A A DispersionStability (1) C C C C C C C Dispersion Stability (2) B B B B B B BClogging Resistance C C C C C C C Reliability (1) Jetting Stability C CC C C C C Rubbing Resistance C C C C C C C Rapid Dryability A A A A A AA

As shown above, the inks of Examples, when used in printing on variouskinds of plain paper and regenerated paper (Yamayuri, Xerox R), providedhigh-quality images with reduced bleeding on the printed images.

On the other hand, the ink in which a pigment is dispersed with ordinarydispersant (Comparative Example 3) and the inks of dye colorant(Comparative Example 4, Comparative Example 5) caused bleeding, andcould not provide high-quality images.

The colorants of the inks of the Examples are insoluble in water.Therefore, as compared with those using a water-soluble dye such asComparative Examples 4 and 5, the images formed by the inks of theExamples have extremely excellent water resistance.

As can be understood from the results in Tables 32 to 49 above, the inksof the Examples produced neither sediments nor foreign substance,exhibited almost no change in their physical properties, and hadsatisfactory dispersion stability and ejection stability.

Specifically, it has been confirmed that satisfactory ejection stabilityand dispersion stability can be attained, firstly, by combining the“colorant of a pigment/and or dye enveloped in a polymer” and the “atleast one compound selected from the group consisting of acetyleneglycol surfactants, acetylene alcohol surfactants, glycol ethers and1,2-alkylene glycols”.

On the other hand, even when the “colorant of pigment/and or dyeenveloped in a polymer” and the “at least one compound selected from thegroup consisting of acetylene glycol surfactants, acetylene alcoholsurfactants, glycol ethers and 1,2-alkylene glycols” were added to anink in which a pigment is dispersed with ordinary dispersant(Comparative Examples 6 to 15), satisfactory dispersion stability andejection stability could not be obtained.

The inks further containing at least one compound selected from thegroup consisting of polyalcohols and compounds of formula (1) exhibitedextremely satisfactory dispersion stability and ejection stability, withalmost no generation of sediments and foreign substance and almost nochange in physical properties.

The inks further containing at least one compound selected fromsaccharide and formula (2), and glycerin exhibited extremelysatisfactory clogging resistance reliability.

When the surface tension thereof was larger than 45 mN/m, the rapiddryability was deteriorated, readily causing bleeding. When the surfacetension was smaller than 25 mN/m, the ejection was not stable. That is,it was confirmed that the surface tension of the ink preferably fallsbetween 25 and 45 mN/m.

<Evaluation Test: Clogging Resistance Reliability (2)>

Regarding the “polymer-enveloped pigment colorants” contained in theinks of Examples 127 to 134, the amount, % by weight, of the “polymer”with respect to the “polymer-enveloped pigment colorant” was varied asshown in Table 50, and those inks were tested for the cloggingresistance reliability. The test method is as follows: Each ink wascharged in the ink cartridge in an ink jet printer, MJ-930C manufacturedby Seiko Epson, left therein at 40° C. and at a humidity of 20% for 3months, and then taken out. Thereafter, the printer was tested in acleaning mode (this is a mode intrinsic to the ink jet printer, MJ-930Jmanufactured by Seiko Epson, for recovering the function of the printerwhen dot deletion or the like occurs), and the number of cleaning modeoperations required for recovering was counted. “A” indicates that theprinter recovered with three times or less operations; “B” indicatesthat the printer recovered with 4 or 5 times operations; “C” indicatesthat the printer recovered with 5 to 20 times operations; and “D”indicates that the printer did not recover even with 20 times or moreoperations.

TABLE 50 Clogging Resistance Reliability (2) amount of polymer (wt. %) 12 5 10 15 20 30 50 Inks with varying Ex. 51 D D C A A A A A amount ofpolymer in Ex. 52 D D C A A A A A colorant Ex. 53 D D C A A A A A Ex. 54D D C A A A A A Ex. 55 D D C A A A A A Ex. 56 D D C A A A A A Ex. 57 D DC A A A A A Ex. 58 D D C A A A A A

As can be seen from the results in Table 50, it was confirmed that whenthe amount of the polymer is 10% by weight or more, particularly, goodclogging recovering property can be obtained.

Regarding the “polymer-enveloped pigment colorants” contained in thecolor inks of Examples 128 to 134, the amount of the polymer was variedas shown in Table 51. Using MJ-930C, solid printing was carried out withthose inks on paper exclusively for OHP (manufactured by Seiko Epson).The measurement results of the haze thereof are shown. The haze wasmeasured with a haze meter (manufactured by Suga Test Instruments).Smaller data indicate lower haze and higher transparency.

TABLE 51 Data of Haze amount of polymer (wt. %) 1 2 5 10 15 20 30 50Inks with varying Ex. 52 25 24 22 13 10 8 7 6 amount of polymer in Ex.53 30 28 25 18 13 10 8 7 colorant Ex. 54 40 37 34 20 17 15 11 9 Ex. 5626 24 22 13 10 8 7 6 Ex. 57 32 32 30 17 14 10 9 8 Ex. 58 43 41 35 20 1812 12 10

As can be seen from the results in Table 51, it was confirmed that whenthe amount of the polymer is 10% by weight or more, particularly, goodcolor transparency with respect to a transparent sheet such as OHP canbe attained.

<Evaluation Test: Rubbing Resistance>

In the preparation of the “polymer-enveloped pigment colorant” containedin the ink of Example 1, the total amount of styrene and butyl acrylatewas kept at 60 parts by weight, but the ratio by weight of styrene tobutyl acrylate was varied as shown in Tables 52 and 53 to thereby varythe glass transition temperature and film-forming temperature of thepolymers. The results of the rubbing resistance evaluation thereof aregiven in Tables 52 and 53.

The film-forming temperature shown therein was measured as follows:Using the head of an ink jet printer, MJ-930C manufactured by SeikoEpson, solid printing was carried out with each ink at 100% duty at apredetermined temperature on an area of 10 mm×10 mm of asuperfine-exclusive glossy film manufactured by Seiko Epson. After theprinted film was then left for 1 hour at the temperature, the printedregion was rubbed with an aqueous yellow fluorescent ink pen, ZEBRA PEN2(trademark) manufactured by Zebra, under a load of 500 g at a speed of10 mm/sec. The temperature at which the printed region was stained wasregarded as the film-forming temperature. The evaluation of the rubbingresistance was made according to the method for the evaluation 7described above.

TABLE 52 glass transition temperature (° C.) 60 40 30 25 20 10 0 St/BA37/23 27/33 21/39 18/42 15/42 9/51 2/58 rubbing resistance C C B A A A ASt/BA: ratio by weight of styrene to butyl acrylate.

TABLE 53 film-forming temperature (° C.) 60 40 30 25 20 10 0 St/BA 37/2327/33 21/39 18/42 15/42 9/51 2/58 rubbing resistance C C B A A A ASt/BA: ratio by weight of styrene to butyl acrylate.

As can be seen from the results in Tables 52 and 53, it was confirmedthat when the glass transition temperature and film-forming temperatureof the polymer part of the colorant are not higher than 25° C.,particularly, good rubbing resistance can be obtained.

In addition, also in the preparation of the “polymer-enveloped pigmentcolorants” contained in the inks of Examples 2 to 4 and 31 to 34, theratio by weight of styrene to butyl acrylate was varied as in Tables 52and 53 above, and the same test was carried out. As a result, almost thesame results as in Tables 52 and 53 were obtained (In the preparation ofthe polymer-enveloped pigment or dye colorants for the inks, the totalamount of styrene and butyl acrylate was 60 parts by weight in Examples2 to 4, and was 65 parts by weight in Examples 31 to 34).

In the preparation of the “polymer-enveloped pigment colorant” containedin the ink of Example 190, the addition amount of the hardlywater-soluble, film-forming promoter, ADEKA PLANON MCP-709 was varied asshown in Tables 54 and 55. The evaluation results of the rubbingresistance thereof are given in Table Tables 54 and 55.

TABLE 54 glass transition temperature (° C.) 40 30 25 20 10 0film-forming promoter (wt. %) 0 10 15 20 30 40 rubbing resistance B B AA A A

TABLE 55 film-forming temperature (° C.) 40 30 25 20 10 0 film-formingpromoter (wt. %) 0 10 15 20 30 40 rubbing resistance B B A A A A

As can be seen from Tables 54 and 55, it was confirmed that when theglass transition temperature and film-forming temperature of the polymerpart of the colorant are not higher than 25° C., particularly, goodrubbing resistance can be attained.

In addition, also in the preparation of the “polymer-enveloped pigmentcolorants” contained in the inks of Examples 191 to 197, thefilm-forming promoter content was varied as in Tables 54 and 55 above,and the same test was carried out. As a result, almost the same resultsas in Tables 54 and 55 were obtained.

<Evaluation Test: Storage Stability>

Using the inks of Examples 198 to 205, and inks prepared by eliminatingtherefrom the preservative, the sequestrant or the rust preventive,evaluation of their storage stability and ejection stability was carriedout. The results are given in Table 56.

For the storage stability, the inks were tested as follows: The ink tobe tested was filled in the cartridge of an ink jet printer, MJ-930Cmanufactured by Seiko Epson, and left at 30° C. for a half year. Afterthus left, the ink was checked as to whether it had a foreign odor andgot mildewed, or not. The case where foreign substance was not at allvisually observed is indicated as “A”, and the case where foreignsubstance was visually observed though its amount was extremely minuteis indicated as “B”. The case where generation of a foreign odor andmildew was not found is indicated as “A”, and the case where generationof a foreign odor and mildew was found is indicated as “B”. The casewhere generation of rust was not found in the nozzle part of the ink jetprinter is indicated as “A”, and the case where generation of rust wasfound therein is indicated as “B”.

TABLE 56 Storage Stability (upper rows: generation of foreign substance,middle rows: generation of foreign odor and mildew, lower rows:generation of rust) Inks of Examples to be based Ex. Ex. Ex. Ex. Ex. Ex.Ex. Ex. 198 199 200 201 202 203 204 205 no change in A A A A A A A Acomposition A A A A A A A A A A A A A A A A preservative A A A A A A A Aomitted B B B B B B B B A A A A A A A A sequestrant B B B B B B B Bomitted A A A A A A A A A A A A A A A A rust preventive A A A A A A A Aomitted A A A A A A A A B B B B B B B B

As can be seen from Table 56, it was confirmed that, particularly, goodstorage stability can be attained with the inks containing apreservative, a sequestrant and an ethylenediamine acetate, wherein thepreservative is at least one compound selected from the group consistingof alkylisothiazolones, chloroalkylisothiazolones, benzisothiazolones,bromonitroalcohols, oxazolidines and chloroxylenols, the sequestrant isethylenediamine acetate, and the rust preventive is dicyclohexylammoniumnitrate and/or benzotriazole.

INDUSTRIAL APPLICABILITY

As has been described hereinabove, the present invention provides an inkjet recording ink, an ink jet recording ink set and a recording method,having excellent dispersion stability and ejection stability and beingcapable of providing a high-quality image which is free from bleedingand has high printed density and excellent color development propertyeven on plain paper and regenerated paper.

Also, the invention provides an ink jet recording ink, an ink jetrecording ink set and a recording method, capable of attainingsatisfactory rubbing resistance not only on plain paper and regeneratedpaper but also on other recording media such as coated paper, etc.

Also, the invention provides an ink jet recording ink and an ink jetrecording ink set, which have excellent long-term storage stability.

Also, the invention provides recorded matter having high-quality imagesof high printed density and excellent color development property, andhaving satisfactory rubbing resistance.

Still also, the invention is to provide an ink jet recording apparatuscapable of producing recorded matter having high-quality images of highprinted density and excellent color development property, and havingsatisfactory rubbing resistance.

The invention claimed is:
 1. An ink jet recording ink comprising: apigment dispersed by a polymer; water; at least one compound selectedfrom the group consisting of an acetylene glycol surfactant and anacetylene alcohol surfactant; and 1,2-hexanediol; wherein the pigmentdispersed by the polymer is produced by a phase conversionemulsification, an emulsion polymerization, an acid deposition or aforced emulsification; wherein the polymer has a glass transitiontemperature of not higher than 15° C; wherein the ink has a surfacetension between 25 mN/m and 45 mN/m; and wherein the polymer has acrosslinked structure.